thescientist--2020-09-02--COVID-19 Antibodies Last for at Least Four Months After Recovery

ABOVE : A panorama of downtown Reykjavik in Iceland .
© ISTOCK.COM , ULTIMA_GAINA A study of COVID-19 patients in Iceland represents the largest effort yet to assess the body ’ s immunological response to infection by SARS-CoV-2 .
Antibodies generated to combat infection peaked in the two months following a positive diagnosis before plateauing for a further two months in more than 90 percent of recovered patients , the authors report .
The findings , published September 1 in the New England Journal of Medicine , partially contradict previous reports of antibodies sharply declining following recovery .
The authors @ @ @ @ @ @ @ it was supplanted by a secondary , more stable wave of antibodies .
If these antibodies remain protective over time , that would have positive implications for vaccine development and immunity to reinfection .
Two experts who weren ’ t involved in the study described the behavior of antibodies over time in an accompanying editorial .
“ The first wave [ of antibodies ] is generated by early short-lived plasma cells .
.
.
but this wave subsides rapidly after resolution of acute infection .
The second wave is generated by a smaller @ @ @ @ @ @ @ long-lived immunity , ” the authors of the editorial report .
“ A rise and early decay of antibodies was observed in the Icelandic study , but with limited loss of antibodies at later time points , a finding that points to stable SARS-CoV-2 immunity for at least 4 months after infection.
” To arrive at this conclusion , the authors sampled more than 30,000 people—roughly 15 percent of Iceland ’ s population—beginning in the early days of the pandemic in February and continuing into early July .
They split their cohort into @ @ @ @ @ @ @ positive COVID-19 diagnosis confirmed by quantitative PCR ( qPCR ) , people who had been exposed to the virus but not necessarily infected , and those without any known exposure .
Each person was tested using six antibody assays , including two that targeted the entire suite of IgG , IgA , and IgM antibodies rather than a single type .
A person was counted as a positive case if those two “ pan-Ig ” assays came back positive .
Based on their findings , the authors estimate that roughly 1 percent of @ @ @ @ @ @ @ with COVID-19 since February , with a fatality rate of 0.3 percent , roughly three times that of the seasonal flu , the Associated Press reports .
The researchers used the subset of roughly 1,200 patients who had received a positive diagnosis by qPCR to track their antibodies over time .
Within this group , 91 percent had antibody levels that rose during the first two months after diagnosis before plateauing for the following two months .
The editorial cautions that populations or even individuals in other countries may not respond the same @ @ @ @ @ @ @ .
Future studies will be needed with more diverse cohorts to see how well their results hold up .
“ That said , this study provides hope that host immunity to this unpredictable and highly contagious virus may not be fleeting and may be similar to that elicited by most other viral infections , ” the authors of the editorial say .
The study did not test whether these longer-lived antibodies are protective against reinfection .
“ What we don ’ t know is really the million-dollar question : How do these antibodies @ @ @ @ @ @ @ of this virus , ” Jason Kindrachuk , a medical microbiologist at the University of Manitoba who wasn ’ t involved with the research , tells NBC News .
“ Just because you see antibodies being produced , it doesn ’ t tell you that those antibodies are going to act specifically against the virus .
”

ABOVE: A panorama of downtown Reykjavik in Iceland. © ISTOCK.COM, ULTIMA_GAINA
A study of COVID-19 patients in Iceland represents the largest effort yet to assess the body’s immunological response to infection by SARS-CoV-2. Antibodies generated to combat infection peaked in the two months following a positive diagnosis before plateauing for a further two months in more than 90 percent of recovered patients, the authors report.
The findings, published September 1 in the New England Journal of Medicine, partially contradict previous reports of antibodies sharply declining following recovery. The authors witnessed that decline as well, but it was supplanted by a secondary, more stable wave of antibodies. If these antibodies remain protective over time, that would have positive implications for vaccine development and immunity to reinfection.
Two experts who weren’t involved in the study described the behavior of antibodies over time in an accompanying editorial. “The first wave [of antibodies] is generated by early short-lived plasma cells . . . but this wave subsides rapidly after resolution of acute infection. The second wave is generated by a smaller number of longer-lived plasma cells that provide long-lived immunity,” the authors of the editorial report. “A rise and early decay of antibodies was observed in the Icelandic study, but with limited loss of antibodies at later time points, a finding that points to stable SARS-CoV-2 immunity for at least 4 months after infection.”
To arrive at this conclusion, the authors sampled more than 30,000 people—roughly 15 percent of Iceland’s population—beginning in the early days of the pandemic in February and continuing into early July. They split their cohort into three groups: those who had a positive COVID-19 diagnosis confirmed by quantitative PCR (qPCR), people who had been exposed to the virus but not necessarily infected, and those without any known exposure.
Each person was tested using six antibody assays, including two that targeted the entire suite of IgG, IgA, and IgM antibodies rather than a single type. A person was counted as a positive case if those two “pan-Ig” assays came back positive.
The current study identified two waves of antibodies associated with a SARS-CoV-2 infection. The New England Journal of Medicine ©2020
Based on their findings, the authors estimate that roughly 1 percent of the population of Iceland has been infected with COVID-19 since February, with a fatality rate of 0.3 percent, roughly three times that of the seasonal flu, the Associated Press reports.
The researchers used the subset of roughly 1,200 patients who had received a positive diagnosis by qPCR to track their antibodies over time. Within this group, 91 percent had antibody levels that rose during the first two months after diagnosis before plateauing for the following two months.
The editorial cautions that populations or even individuals in other countries may not respond the same way to SARS-CoV-2 infection as in Iceland. Future studies will be needed with more diverse cohorts to see how well their results hold up. “That said, this study provides hope that host immunity to this unpredictable and highly contagious virus may not be fleeting and may be similar to that elicited by most other viral infections,” the authors of the editorial say.
The study did not test whether these longer-lived antibodies are protective against reinfection. “What we don’t know is really the million-dollar question: How do these antibodies reflect immunity against this virus and inhibition of this virus,” Jason Kindrachuk, a medical microbiologist at the University of Manitoba who wasn’t involved with the research, tells NBC News. “Just because you see antibodies being produced, it doesn’t tell you that those antibodies are going to act specifically against the virus.”


thescientist--2020-09-02--Toward COVID-19 Testing Any Time, Anywhere

ABOVE : A mockup of the at-home test currently under development by Mammoth Biosciences and GlaxoSmithKline MAMMOTH BIOSCIENCES In late January , as the COVID-19 pandemic was gaining steam , Charles Chiu , a researcher at the University of California , San Francisco , reached out to colleagues at San Francisco–based biotech Mammoth Biosciences .
Chiu ’ s group and the team at Mammoth had already collaborated on developing a CRISPR-based diagnostic test for Lyme disease , which they thought would easily translate to SARS-CoV-2 detection , he says .
“ The CRISPR system allows you to target pathogens very @ @ @ @ @ @ @ part of Mammoth ’ s scientific advisory board , tells The Scientist .
“ Within two to three weeks , we were able to go from just designing the assay to actually getting it to work and demonstrating that we can use it to rapidly identify or potentially diagnose SARS-CoV-2 from clinical samples.
” The gold standard for detecting a virus such as SARS-CoV-2 is reverse transcription PCR , which requires isolation of RNA from a sample followed by the conversion of RNA to DNA and subsequent PCR to amplify any viral nucleic @ @ @ @ @ @ @ of test requires collection of a specimen , such as saliva or a nasal swab , and the transport of that sample to a clinical lab for processing .
Earlier in the year , reagents for this type of test were in short supply .
The new assay developed by Chiu and colleagues is called SARS-CoV-2 DETECTR ( for SARS-CoV-2 DNA endonuclease-targeted CRISPR trans reporter ) ; researchers published details about how it works in Nature Biotechnology on April 16 .
The test is fast : after RNA extraction , it takes less @ @ @ @ @ @ @ .
And it uses loop-mediated amplification ( LAMP ) , which takes place at just one temperature , rather than the cycling temperatures necessary for PCR , meaning an expensive thermocycler is not required .
The enzyme most commonly used for CRISPR genetic modification is Cas9 , which , guided by a short RNA sequence , finds and cleaves a nucleic acid target .
DETECTR uses a different enzyme , Cas12 , which also follows a guide RNA to its target—in this case , SARS-CoV-2 sequences—but cleaves more than just its target ; @ @ @ @ @ @ @ acids .
The assay includes a reporter molecule that , when it gets cleaved by Cas12 during the cutting frenzy precipitated by SARS-CoV-2 nucleic acid recognition , can be visualized on a test strip , similar to a home pregnancy test .
In their paper , the authors reported that the sensitivity of DETECTR was comparable to a reverse transcription PCR assay run in a clinical lab on about 80 patient samples .
On July 9 , the assay was given emergency use authorization ( EUA ) by the US Food and Drug @ @ @ @ @ @ @ use at the University of California , San Francisco ’ s clinical lab .
Since then , the developers have continued to focus on making the test more accessible and easier to use .
In the iteration that was approved for EUA , there ’ s still an RNA extraction step , Chiu explains .
That ’ s a possible issue because “ there was a shortage of extraction reagents just a month or two ago , and it ’ s also limited by the fact that extractions typically take anywhere from a @ @ @ @ @ @ @ so .
.
.
we ended up modifying this test so that we can actually run the LAMP reaction directly from [ an ] original sample.
” See “ The Push to Deploy At-Home Antigen Tests for COVID-19 ” On May 20 , Mammoth Biosciences established a partnership with pharmaceutical company GlaxoSmithKline Consumer Healthcare to further develop DETECTR into a handheld , disposable device that would be appropriate for home use and be about as expensive as an at-home pregnancy test .
“ The way point-of-need and at-home diagnostics will work is if @ @ @ @ @ @ @ says Trevor Martin , Mammoth Biosciences ’ s CEO .
“ It needs to be as easy to use as a pregnancy test , and we ’ re also very much believers that it needs to give you results that are as trusted and accurate as something you would get in the lab.
” Since the COVID-19 pandemic started to take off in the US in March , testing has largely focused on people who already have symptoms , partly because resources are limited .
The trouble is , it seems as though @ @ @ @ @ @ @ time of symptom onset , meaning that if people are waiting to quarantine or take other protective measures until they get a positive result , they may have already infected others .
Testing at the earliest stage of symptoms “ is useful from an epidemiological perspective to understand how COVID impacts patients , ” says Rahul Dhanda , the CEO of Sherlock Biosciences , a Cambridge , Massachusetts–based biotech that develops diagnostics and is now focusing on SARS-CoV-2 .
“ But in terms of prevention and tracking the history of disease , what @ @ @ @ @ @ @ who are asymptomatic.
” Toward the goal of catching more cases before they spread and avoiding supply chain issues , a number of biotechs and academic labs are devising new strategies and exploiting existing technology to make testing simpler and available in settings other than doctors ’ offices and clinical labs .
See “ Saliva Tests : How They Work and What They Bring to COVID-19 ” In a study published in PLOS Pathogens on August 27 , for instance , a group based in China described a test that relies on RNA @ @ @ @ @ @ @ assay leverages Cas13a , an enzyme that behaves similarly to Cas12 to cleave a single-stranded reporter that fluoresces when SARS-CoV-2 RNA is present , and another type of isothermal ( constant temperature ) amplification , reverse transcription recombinase polymerase amplification .
In the study , the authors estimate the cost of one CRISPR-COVID test at about $ 3.50 , but predict it could be as low as $ 0.70 if the reagents were purchased in bulk .
The current version is most appropriate for the lab , as it requires an RNA extraction @ @ @ @ @ @ @ fluorescent signals .
In a study published August 31 in PNAS , researchers developed a test that uses LAMP directly on patient samples and detects SARS-CoV-2 with a microfluidic cartridge and portable smartphone-based reader .
Because it does not require RNA extraction or PCR amplification , “ this approach could enable the scalable deployment of COVID-19 diagnostics without laboratory-grade infrastructure and resources , especially in settings where diagnosis is required at the point of collection , such as schools , facilities that care for the elderly or disabled , or sporting events , @ @ @ @ @ @ @ pandemic is not the first time LAMP has been developed for diagnosing viral infections .
Because of its portability , it ’ s been deployed in Ebola and Zika outbreaks .
But the technology is not without drawbacks .
“ There are a couple of problems with isothermal amplification , ” cautions Max Wilson , a biologist at the University of California , Santa Barbara ( UCSB ) .
Wilson has developed a COVID-19 test in use at UCSB that uses CRISPR for detection and PCR for amplification .
“ In our hands @ @ @ @ @ @ @ less sensitive than other amplification methods , ” he explains .
Another problem is that if everyone starts using LAMP , the reagents , which aren ’ t made at volumes supportive of pandemic-scale testing , could become harder to get , Wilson says .
“ The production has not been streamlined and optimized.
” Despite these and other issues , “ there are a lot of really promising and complementary testing frameworks ” out there , he adds .
All of the various approaches—at-home testing , lab-based testing of samples taken at @ @ @ @ @ @ @ be used to test thousands of people daily , such as in public health departments or at big universities— “ don ’ t even compete for resources or manufacturing capability , ” Wilson says , “ and they ’ re all necessary.
” “ There ’ s a huge amount of unmet need ” when it comes to COVID-19 testing , Martin agrees .
“ We just need all hands on deck.
” Starting in mid-March , Dhanda and his team at Sherlock Biosciences pivoted their entire research program to focus on developing @ @ @ @ @ @ @ platform SHERLOCK , which stands for specific high sensitivity enzymatic reporter unlocking .
On May 6 , that kit granted EUA and is now distributed in the US through a collaboration with Integrated DNA Technologies .
Because that test still includes a lot of steps , most of which are best performed in a lab , the researchers are now also working on a room-temperature , instrument-free test , the output of which can be visualized on a paper strip .
That technology , which is called INSPECTR for internal splint-pairing expression cassette @ @ @ @ @ @ @ the Wyss Institute at Harvard University and relies on hybridization of a sample , such as saliva , to freeze-dried synthetic DNA complementary to SARS-CoV-2 RNA .
If the sample contains viral RNA , a reporter protein is activated and then can be visualized with the naked eye , making the test a great option for eventual home use .
“ The fact that you can do a molecular diagnostic test in the palm of your hands is something that has never been possible before , ” says Dhanda , who adds that @ @ @ @ @ @ @ EUA once development is finished , probably early next year .
How much it will cost hasn ’ t been disclosed , but a company representative tells The Scientist that Sherlock is committed to making the test accessible .
In a study published in Science Advances on August 25 , a group of researchers led by University of Albany biomedical engineer Ken Halvorsen also used a synthetic DNA approach to detect viral RNA , both from Zika virus and from SARS-CoV-2 .
The authors created DNA nanoswitches , small bits of DNA that @ @ @ @ @ @ @ a target sequence .
Because of the shape change , samples that contain viral RNA look different when run during gel electrophoresis than do samples without virus .
“ We can use this approach to detect viruses at levels that are relevant for health , ” Halvorsen says .
The group is now “ trying to figure out how we can do a workflow that will allow us to do the whole thing outside of a lab.
” Because the test can be performed without enzymes , it already lends itself to streamlining @ @ @ @ @ @ @ readout , possibly using some type of cartridge that could be preconstructed , portable , and disposable .
“ We ’ re hoping to get the whole process down to under an hour , ” he tells The Scientist .
As for competition , “ I don ’ t think that the testing for coronavirus is going to be a winner-take-all situation , ” Halvorsen says .
“ There really need to be lots of different options .
And it may turn out that there are many different testing types that all work @ @ @ @ @ @ @ .
“ This may not be a short-term problem .
We may be testing for years.
” See “ U of Illinois Returns to School with 20,000 Saliva Tests Per Day ”

ABOVE: A mockup of the at-home test currently under development by Mammoth Biosciences and GlaxoSmithKline
MAMMOTH BIOSCIENCES
In late January, as the COVID-19 pandemic was gaining steam, Charles Chiu, a researcher at the University of California, San Francisco, reached out to colleagues at San Francisco–based biotech Mammoth Biosciences. Chiu’s group and the team at Mammoth had already collaborated on developing a CRISPR-based diagnostic test for Lyme disease, which they thought would easily translate to SARS-CoV-2 detection, he says.
“The CRISPR system allows you to target pathogens very precisely,” Chiu, who is part of Mammoth’s scientific advisory board, tells The Scientist. “Within two to three weeks, we were able to go from just designing the assay to actually getting it to work and demonstrating that we can use it to rapidly identify or potentially diagnose SARS-CoV-2 from clinical samples.”
The gold standard for detecting a virus such as SARS-CoV-2 is reverse transcription PCR, which requires isolation of RNA from a sample followed by the conversion of RNA to DNA and subsequent PCR to amplify any viral nucleic acids. While sensitive, this type of test requires collection of a specimen, such as saliva or a nasal swab, and the transport of that sample to a clinical lab for processing. Earlier in the year, reagents for this type of test were in short supply.
The new assay developed by Chiu and colleagues is called SARS-CoV-2 DETECTR (for SARS-CoV-2 DNA endonuclease-targeted CRISPR trans reporter); researchers published details about how it works in Nature Biotechnology on April 16. The test is fast: after RNA extraction, it takes less than an hour to get a result. And it uses loop-mediated amplification (LAMP), which takes place at just one temperature, rather than the cycling temperatures necessary for PCR, meaning an expensive thermocycler is not required.
The enzyme most commonly used for CRISPR genetic modification is Cas9, which, guided by a short RNA sequence, finds and cleaves a nucleic acid target. DETECTR uses a different enzyme, Cas12, which also follows a guide RNA to its target—in this case, SARS-CoV-2 sequences—but cleaves more than just its target; it also starts chopping up nearby nucleic acids. The assay includes a reporter molecule that, when it gets cleaved by Cas12 during the cutting frenzy precipitated by SARS-CoV-2 nucleic acid recognition, can be visualized on a test strip, similar to a home pregnancy test.
In their paper, the authors reported that the sensitivity of DETECTR was comparable to a reverse transcription PCR assay run in a clinical lab on about 80 patient samples. On July 9, the assay was given emergency use authorization (EUA) by the US Food and Drug Administration (FDA), only for use at the University of California, San Francisco’s clinical lab. Since then, the developers have continued to focus on making the test more accessible and easier to use.
In the iteration that was approved for EUA, there’s still an RNA extraction step, Chiu explains. That’s a possible issue because “there was a shortage of extraction reagents just a month or two ago, and it’s also limited by the fact that extractions typically take anywhere from a half an hour to an hour, so . . . we ended up modifying this test so that we can actually run the LAMP reaction directly from [an] original sample.”
On May 20, Mammoth Biosciences established a partnership with pharmaceutical company GlaxoSmithKline Consumer Healthcare to further develop DETECTR into a handheld, disposable device that would be appropriate for home use and be about as expensive as an at-home pregnancy test.
“The way point-of-need and at-home diagnostics will work is if they’re truly all-in-one,” says Trevor Martin, Mammoth Biosciences’s CEO. “It needs to be as easy to use as a pregnancy test, and we’re also very much believers that it needs to give you results that are as trusted and accurate as something you would get in the lab.”
Amplifying without PCR
Since the COVID-19 pandemic started to take off in the US in March, testing has largely focused on people who already have symptoms, partly because resources are limited. The trouble is, it seems as though the virus is most contagious around the time of symptom onset, meaning that if people are waiting to quarantine or take other protective measures until they get a positive result, they may have already infected others.
Testing at the earliest stage of symptoms “is useful from an epidemiological perspective to understand how COVID impacts patients,” says Rahul Dhanda, the CEO of Sherlock Biosciences, a Cambridge, Massachusetts–based biotech that develops diagnostics and is now focusing on SARS-CoV-2. “But in terms of prevention and tracking the history of disease, what you want to do is test people who are asymptomatic.”
Toward the goal of catching more cases before they spread and avoiding supply chain issues, a number of biotechs and academic labs are devising new strategies and exploiting existing technology to make testing simpler and available in settings other than doctors’ offices and clinical labs.
In a study published in PLOS Pathogens on August 27, for instance, a group based in China described a test that relies on RNA extraction that they call CRISPR-COVID. Their assay leverages Cas13a, an enzyme that behaves similarly to Cas12 to cleave a single-stranded reporter that fluoresces when SARS-CoV-2 RNA is present, and another type of isothermal (constant temperature) amplification, reverse transcription recombinase polymerase amplification. In the study, the authors estimate the cost of one CRISPR-COVID test at about $3.50, but predict it could be as low as $0.70 if the reagents were purchased in bulk. The current version is most appropriate for the lab, as it requires an RNA extraction step and specialized equipment to pick up fluorescent signals.
The fact that you can do a molecular diagnostic test in the palm of your hands is something that has never been possible before. —Rahul Dhanda, the CEO of Sherlock Biosciences
In a study published August 31 in PNAS, researchers developed a test that uses LAMP directly on patient samples and detects SARS-CoV-2 with a microfluidic cartridge and portable smartphone-based reader. Because it does not require RNA extraction or PCR amplification, “this approach could enable the scalable deployment of COVID-19 diagnostics without laboratory-grade infrastructure and resources, especially in settings where diagnosis is required at the point of collection, such as schools, facilities that care for the elderly or disabled, or sporting events,” the authors write.
The current pandemic is not the first time LAMP has been developed for diagnosing viral infections. Because of its portability, it’s been deployed in Ebola and Zika outbreaks. But the technology is not without drawbacks. “There are a couple of problems with isothermal amplification,” cautions Max Wilson, a biologist at the University of California, Santa Barbara (UCSB). Wilson has developed a COVID-19 test in use at UCSB that uses CRISPR for detection and PCR for amplification. “In our hands . . . [LAMP] is less sensitive than other amplification methods,” he explains.
Another problem is that if everyone starts using LAMP, the reagents, which aren’t made at volumes supportive of pandemic-scale testing, could become harder to get, Wilson says. “The production has not been streamlined and optimized.”
Despite these and other issues, “there are a lot of really promising and complementary testing frameworks” out there, he adds. All of the various approaches—at-home testing, lab-based testing of samples taken at healthcare facilities, and assays that could be used to test thousands of people daily, such as in public health departments or at big universities—“don’t even compete for resources or manufacturing capability,” Wilson says, “and they’re all necessary.”
“There’s a huge amount of unmet need” when it comes to COVID-19 testing, Martin agrees. “We just need all hands on deck.”
Leveraging synthetic biology
Starting in mid-March, Dhanda and his team at Sherlock Biosciences pivoted their entire research program to focus on developing a CRISPR-based COVID-19 test kit using their platform SHERLOCK, which stands for specific high sensitivity enzymatic reporter unlocking. On May 6, that kit granted EUA and is now distributed in the US through a collaboration with Integrated DNA Technologies.
Because that test still includes a lot of steps, most of which are best performed in a lab, the researchers are now also working on a room-temperature, instrument-free test, the output of which can be visualized on a paper strip. That technology, which is called INSPECTR for internal splint-pairing expression cassette translation reaction, was originally developed at the Wyss Institute at Harvard University and relies on hybridization of a sample, such as saliva, to freeze-dried synthetic DNA complementary to SARS-CoV-2 RNA. If the sample contains viral RNA, a reporter protein is activated and then can be visualized with the naked eye, making the test a great option for eventual home use.
A design concept of INSPECTR Wyss Institute at Harvard University
“The fact that you can do a molecular diagnostic test in the palm of your hands is something that has never been possible before,” says Dhanda, who adds that they are planning to apply for an EUA once development is finished, probably early next year. How much it will cost hasn’t been disclosed, but a company representative tells The Scientist that Sherlock is committed to making the test accessible.
In a study published in Science Advances on August 25, a group of researchers led by University of Albany biomedical engineer Ken Halvorsen also used a synthetic DNA approach to detect viral RNA, both from Zika virus and from SARS-CoV-2. The authors created DNA nanoswitches, small bits of DNA that change their shape in response to binding a target sequence. Because of the shape change, samples that contain viral RNA look different when run during gel electrophoresis than do samples without virus.
“We can use this approach to detect viruses at levels that are relevant for health,” Halvorsen says. The group is now “trying to figure out how we can do a workflow that will allow us to do the whole thing outside of a lab.” Because the test can be performed without enzymes, it already lends itself to streamlining, and they plan to simplify the readout, possibly using some type of cartridge that could be preconstructed, portable, and disposable. “We’re hoping to get the whole process down to under an hour,” he tells The Scientist.
As for competition, “I don’t think that the testing for coronavirus is going to be a winner-take-all situation,” Halvorsen says. “There really need to be lots of different options. And it may turn out that there are many different testing types that all work in different situations,” he adds. “This may not be a short-term problem. We may be testing for years.”


thescientist--2020-09-03--HEPA Filters Help Prevent Aerosol DNA Contamination

Many laboratories use biosafety cabinets to limit contamination risks for sensitive and susceptible experiments .
Biosafety cabinets rely on HEPA @ @ @ @ @ intake air in order to create a controlled environment for experimental manipulation .
HEPA filters @ @ @ @ @ , so particles smaller than that threshold will not be removed .
Researchers have therefore @ @ @ @ @ elude HEPA filters .
Download this white paper to explore how effective HEPA filters are @ @ @ @ @ .

Many laboratories use biosafety cabinets to limit contamination risks for sensitive and susceptible experiments. Biosafety cabinets rely on HEPA filters to remove contaminants from intake air in order to create a controlled environment for experimental manipulation. HEPA filters come with particle size thresholds, so particles smaller than that threshold will not be removed. Researchers have therefore speculated that aerosolized DNA may elude HEPA filters.
Download this white paper to explore how effective HEPA filters are at removing aerosolized DNA particles.


thescientist--2020-09-03--Steroid Drugs Are an Effective Treatment for Severe COVID-19: WHO

Dexamethasone and other corticosteroid drugs are effective treatments for seriously ill COVID-19 patients , according to a meta-analysis of seven randomized controlled trials including a total of more than 1,700 participants .
The analysis , conducted by a team at the World Health Organization ( WHO ) and published yesterday ( September 2 ) in JAMA , concluded that the drugs reduced the risk of dying within 28 days compared with standard care or placebo .
The organization has issued new guidelines recommending use of the drugs in the treatment of patients with severe or critical COVID-19 .
“ Steroids @ @ @ @ @ @ @ , and our analysis has confirmed that they are effective in reducing deaths amongst the people most severely affected by Covid-19 , ” Jonathan Sterne , a professor of medicine and epidemiology at Bristol University who helped conduct the meta-analysis , tells The Guardian .
“ The results were consistent across the trials and show benefit regardless of age or sex.
” Dexamethasone has been in use in hospitals as a COVID-19 treatment for seriously ill patients for several months now , after the UK RECOVERY trial reported in June that the drug @ @ @ @ @ @ @ to require mechanical ventilation .
The new meta-analysis reviewed data from this and two other trials of dexamethasone , plus three trials of hydrocortisone and one small study of methylprednisolone .
All three drugs are often prescribed by doctors to help dampen inflammation and other immune system responses .
They had been proposed as potential COVID-19 treatments partly because patients who die from the disease often succumb to overreactive immune responses .
The WHO has cautioned that the findings do not mean that steroids should be given to all COVID-19 patients , and @ @ @ @ @ @ @ prescribe the drugs to people with mild disease .
One study included in the meta-analysis found that corticosteroids might even increase mortality in non-severe patients .
See “ Insight into Dexamethasone ’ s Benefits in Severe COVID-19 ” It ’ s still not clear exactly when steroids should be given to patients with worsening disease for the best outcome , Nahid Bhadelia , the medical director of the Special Pathogens Unit at the Boston University School of Medicine , tells STAT .
For patients who don ’ t yet require oxygen support but @ @ @ @ @ @ @ , “ it would be interesting to know if co-administration of an antiviral may help reduce viral load while the earlier steroids work on the inflammatory component , ” Bhadelia adds .

ABOVE: © ISTOCK.COM, DIGICOMPHOTO
Dexamethasone and other corticosteroid drugs are effective treatments for seriously ill COVID-19 patients, according to a meta-analysis of seven randomized controlled trials including a total of more than 1,700 participants. The analysis, conducted by a team at the World Health Organization (WHO) and published yesterday (September 2) in JAMA, concluded that the drugs reduced the risk of dying within 28 days compared with standard care or placebo. The organization has issued new guidelines recommending use of the drugs in the treatment of patients with severe or critical COVID-19.
“Steroids are a cheap and readily available medication, and our analysis has confirmed that they are effective in reducing deaths amongst the people most severely affected by Covid-19,” Jonathan Sterne, a professor of medicine and epidemiology at Bristol University who helped conduct the meta-analysis, tells The Guardian. “The results were consistent across the trials and show benefit regardless of age or sex.”
Dexamethasone has been in use in hospitals as a COVID-19 treatment for seriously ill patients for several months now, after the UK RECOVERY trial reported in June that the drug reduced mortality in COVID-19 patients ill enough to require mechanical ventilation.
The new meta-analysis reviewed data from this and two other trials of dexamethasone, plus three trials of hydrocortisone and one small study of methylprednisolone. All three drugs are often prescribed by doctors to help dampen inflammation and other immune system responses. They had been proposed as potential COVID-19 treatments partly because patients who die from the disease often succumb to overreactive immune responses.
The WHO has cautioned that the findings do not mean that steroids should be given to all COVID-19 patients, and the organization currently recommends doctors not to prescribe the drugs to people with mild disease. One study included in the meta-analysis found that corticosteroids might even increase mortality in non-severe patients.
It’s still not clear exactly when steroids should be given to patients with worsening disease for the best outcome, Nahid Bhadelia, the medical director of the Special Pathogens Unit at the Boston University School of Medicine, tells STAT.
For patients who don’t yet require oxygen support but maybe be developing an overreactive immune response, “it would be interesting to know if co-administration of an antiviral may help reduce viral load while the earlier steroids work on the inflammatory component,” Bhadelia adds.


thescientist--2020-09-03--New Drug Combo for ALS Slows Decline in Small Clinical Study

A trial of 137 patients with amyotrophic lateral sclerosis showed that a new combination of an existing drug and a supplement lessened declines in a standard measure of function over six months , according to a study published today ( September 3 ) in The New England Journal of Medicine .
While the effect was modest and the trial early stage , “ I am convinced that we are at the beginning of a new era in ALS treatment discovery , ” Sabrina Paganoni , a researcher at the Sean Healey & AMG Center for ALS at Massachusetts General Hospital @ @ @ @ @ @ @ study , tells NPR .
“ [ Patients ] want to be able to continue to use their hands so they can cut their own food and type emails , or they want to be able to walk and climb stairs , and this is exactly what we measured in the trial.
” There are currently two approved drugs to treat ALS : riluzole , which can extend lifespan by an average of a few months and has been on the market for 25 years , and the 2017-approved edaravone , which was @ @ @ @ @ @ @ function for longer into their disease .
Even with these treatment options , ALS is still a death sentence for most patients , typically within three to five years of diagnosis .
The new drug combo , called AMX0035 , was conceived by Joshua Cohen and Justin Klee as undergraduates at Brown University several years ago and is now being developed by the company they founded , Cambridge , Massachusetts–based Amylyx .
The treatment includes sodium phenylbutrate , which is a medication for urea cycle disorders , and the supplement taurursodiol—a combo that @ @ @ @ @ @ @ biomedical engineer major would maintain functioning of the mitochondria and endoplasmic reticulum to protect against neuronal damage , The New York Times reports .
The data from the trial suggested it might be working .
In six months , patients who had received AMX0035 saw a smaller decline in the ALS Functional Rating Scale , which assesses a patient ’ s ability to do activities such as swallow and climb stairs , than those in the placebo group—about 2.9 points less , on average .
Most also saw improvement in certain fine motor @ @ @ @ @ @ @ in a couple of points can mean a large change in what daily life looks like , ” Paganoni tells STAT .
“ This is very encouraging , ” Neil Shneider , the director of the Eleanor and Lou Gehrig A.L.S .
Center at Columbia University who did not participate in the study , tells the Times .
“ The question is , is the effect on function sustained beyond the six-month trial period and does it have an effect on survival ?
” Matthew Kiernan , chair of neurology at the University @ @ @ @ @ @ @ in the research , points out to STAT that the trial found no evidence that the treatment improved patients ’ ability to breathe , but says he awaits future results from Amylyx .
Most of the patients in the trial were already taking an approved drug , and they continued their normal regimen throughout the trial of AMX0035 .
Merit Cudkowicz , director of the Healey Center and senior author of the study , tells the Times that , if approved , the new treatment would likely be used in combination with existing @ @ @ @ @ @ @ supported with funds from the ALS Association that were generated by the Ice Bucket Challenge , the Times reports , and if the drug is approved , Amylyx will repay 150 percent of the ALS Association ’ s funding to support additional research .
“ What makes this time so exciting is there are over 50 different clinical trials that are enrolling and recruiting ALS patients right now , ” Kuldip Dave , the ALS Association ’ s vice president of research , tells NPR .
“ And they ’ re all going @ @ @ @ @

ABOVE: © ISTOCK.COM, PEOPLEIMAGES
A trial of 137 patients with amyotrophic lateral sclerosis showed that a new combination of an existing drug and a supplement lessened declines in a standard measure of function over six months, according to a study published today (September 3) in The New England Journal of Medicine.
While the effect was modest and the trial early stage, “I am convinced that we are at the beginning of a new era in ALS treatment discovery,” Sabrina Paganoni, a researcher at the Sean Healey & AMG Center for ALS at Massachusetts General Hospital and Harvard Medical School who led the study, tells NPR. “[Patients] want to be able to continue to use their hands so they can cut their own food and type emails, or they want to be able to walk and climb stairs, and this is exactly what we measured in the trial.”
There are currently two approved drugs to treat ALS: riluzole, which can extend lifespan by an average of a few months and has been on the market for 25 years, and the 2017-approved edaravone, which was shown in clinical trials to help patients function for longer into their disease. Even with these treatment options, ALS is still a death sentence for most patients, typically within three to five years of diagnosis.
The new drug combo, called AMX0035, was conceived by Joshua Cohen and Justin Klee as undergraduates at Brown University several years ago and is now being developed by the company they founded, Cambridge, Massachusetts–based Amylyx. The treatment includes sodium phenylbutrate, which is a medication for urea cycle disorders, and the supplement taurursodiol—a combo that Cohen hypothesized back in 2013 as a biomedical engineer major would maintain functioning of the mitochondria and endoplasmic reticulum to protect against neuronal damage, The New York Times reports.
The data from the trial suggested it might be working. In six months, patients who had received AMX0035 saw a smaller decline in the ALS Functional Rating Scale, which assesses a patient’s ability to do activities such as swallow and climb stairs, than those in the placebo group—about 2.9 points less, on average. Most also saw improvement in certain fine motor skills. “Even a small change in a couple of points can mean a large change in what daily life looks like,” Paganoni tells STAT.
“This is very encouraging,” Neil Shneider, the director of the Eleanor and Lou Gehrig A.L.S. Center at Columbia University who did not participate in the study, tells the Times. “The question is, is the effect on function sustained beyond the six-month trial period and does it have an effect on survival?” Matthew Kiernan, chair of neurology at the University of Sydney who was also not involved in the research, points out to STAT that the trial found no evidence that the treatment improved patients’ ability to breathe, but says he awaits future results from Amylyx.
Most of the patients in the trial were already taking an approved drug, and they continued their normal regimen throughout the trial of AMX0035. Merit Cudkowicz, director of the Healey Center and senior author of the study, tells the Times that, if approved, the new treatment would likely be used in combination with existing medications.
The trial was the first supported with funds from the ALS Association that were generated by the Ice Bucket Challenge, the Times reports, and if the drug is approved, Amylyx will repay 150 percent of the ALS Association’s funding to support additional research.
“What makes this time so exciting is there are over 50 different clinical trials that are enrolling and recruiting ALS patients right now,” Kuldip Dave, the ALS Association’s vice president of research, tells NPR. “And they’re all going after different targets.”


thescientist--2020-09-04--Panel Lays Out Guidelines for CRISPR-Edited Human Embryos

On Thursday ( September 3 ) , the International Commission on the Clinical Use of Human Germline Genome Editing released a report that reviews the available research and determines gene editing ’ s ethical use on human embryos .
The 225-page document offers a roadmap to the testing and regulations necessary to develop the technology and ultimately concludes that the technology is not yet reliable enough to use on humans .
Any country that permits its scientists to do so in the future should limit the activity to severe single-gene diseases .
The commission , composed of dozens of scientists @ @ @ @ @ @ @ He Jiankui claimed in 2018 to have used CRISPR-Cas9 on a set of twins and a third baby to make them HIV-resistant .
While the validity of the editing has yet to be determined , He ’ s claims have been met with international condemnation and a three-year prison sentence for illegally practicing medicine .
Somatic gene editing introduces altered DNA into some of the body ’ s cells post-development as a means to treat genetic conditions .
Germline editing manipulates DNA in the earliest stages of embryonic development , affects all tissue @ @ @ @ @ @ @ then pass down those alterations to their offspring .
Instead of treating the disease , germline editing would theoretically be able to eliminate it not only from the organism but from its lineage completely , making it attractive in the context of heritable genetic diseases .
Although manipulating genomes via CRISPR has become commonplace in genetic labs around the world , the commission states that , currently , “ the outcomes of genome editing in human zygotes can not be adequately controlled ” and could bear unintended consequences .
“ It underscores what @ @ @ @ @ @ @ about this are aware of : There must not be any use of germline editing for clinical purposes at this time , ” Jennifer Doudna , a geneticist at the University of California , Berkeley , who was not a member of the commission , tells STAT .
“ And the reason is the technology is just too early-stage and we don ’ t understand well enough how it works in human embryos.
” Once it is possible to safely make these changes , the commission advises , countries could adopt policies allowing @ @ @ @ @ @ @ a single gene is responsible for the disorder , such as sickle cell anemia , cystic fibrosis , or Tay-Sachs .
“ We think the bar should be high , and appropriately so , ” Richard Lifton , cochair of the panel , tells The Guardian .
“ If you are going to be creating human beings , you want to know that you can reliably make the edits you ’ re intending .
If you can ’ t do it reliably , without introducing unintended effects , you shouldn ’ t be @ @ @ @ @ @

ABOVE: © ISTOCK.COM, POSTERIORI
On Thursday (September 3), the International Commission on the Clinical Use of Human Germline Genome Editing released a report that reviews the available research and determines gene editing’s ethical use on human embryos. The 225-page document offers a roadmap to the testing and regulations necessary to develop the technology and ultimately concludes that the technology is not yet reliable enough to use on humans. Any country that permits its scientists to do so in the future should limit the activity to severe single-gene diseases.
The commission, composed of dozens of scientists worldwide, was formed after Chinese geneticist He Jiankui claimed in 2018 to have used CRISPR-Cas9 on a set of twins and a third baby to make them HIV-resistant. While the validity of the editing has yet to be determined, He’s claims have been met with international condemnation and a three-year prison sentence for illegally practicing medicine.
Somatic gene editing introduces altered DNA into some of the body’s cells post-development as a means to treat genetic conditions. Germline editing manipulates DNA in the earliest stages of embryonic development, affects all tissue types, and permits the organism to then pass down those alterations to their offspring. Instead of treating the disease, germline editing would theoretically be able to eliminate it not only from the organism but from its lineage completely, making it attractive in the context of heritable genetic diseases.
Although manipulating genomes via CRISPR has become commonplace in genetic labs around the world, the commission states that, currently, “the outcomes of genome editing in human zygotes cannot be adequately controlled” and could bear unintended consequences.
“It underscores what really I think most researchers who think about this are aware of: There must not be any use of germline editing for clinical purposes at this time,” Jennifer Doudna, a geneticist at the University of California, Berkeley, who was not a member of the commission, tells STAT. “And the reason is the technology is just too early-stage and we don’t understand well enough how it works in human embryos.”
Once it is possible to safely make these changes, the commission advises, countries could adopt policies allowing this technology only for the cases when a single gene is responsible for the disorder, such as sickle cell anemia, cystic fibrosis, or Tay-Sachs.
“We think the bar should be high, and appropriately so,” Richard Lifton, cochair of the panel, tells The Guardian. “If you are going to be creating human beings, you want to know that you can reliably make the edits you’re intending. If you can’t do it reliably, without introducing unintended effects, you shouldn’t be going [forward].”


thescientist--2020-09-04--Roger Unger, Endocrinologist and Authority on Diabetes, Dies

Roger Unger , who studied the hormonal underpinnings of diabetes for more than 60 years , died on August 22 at age 96 .
During his long tenure at the University of Texas Southwestern ( UTSW ) Medical Center that ended in July when he retired , he discovered the roles of the hormones glucagon and insulin in controlling blood sugar levels in the body .
Born in 1924 in New York , Unger attended Yale University and Columbia University during his medical training before spending the majority of his professional career at UTSW , where he was one of @ @ @ @ @ @ @ the founding director of the Touchstone Diabetes Center , and his work helped elevate the institution to a world leader in the study and treatment of diabetes and related endocrine disorders .
For his significant contributions to the field , he was awarded several honors , including the Banting Medal ( 1975 ) , the Claude Bernard Memorial Medal ( 1980 ) , the Fred Conrad Koch Award ( 1983 ) , and the Rolf Luft Award in 2014 from the Karolinska Institute .
“ Dr .
Unger was a visionary endocrinologist who @ @ @ @ @ @ @ the field for more than 60 years , ” Daniel Podolsky , president of UTSW , shared in an obituary .
“ His outstanding contributions in endocrinology and metabolism set the foundation for many of the important discoveries in these areas.
” Shortly after joining UTSW in 1956 , Unger carried out experiments establishing glucagon as a true hormone involved in glucose production .
Following this link , he next demonstrated the bihormonal nature of diabetes , showing that the high blood sugar characteristic of the disease stems not only from a lack @ @ @ @ @ @ @ of glucagon that increases glucose production .
More recently , he had shown that blood glucose could not rise without abnormally high levels of glucagon .
“ Glucagon is the main culprit in diabetes , and if we can block its action , diabetes vanishes , ” Unger said in a 2018 video about his work .
Throughout his career , he also focused on the interplay between obesity , diabetes , and metabolic syndrome , studying how combinations of risk factors led to the development of heart disease and type 2 diabetes @ @ @ @ @ @ @ the concept of lipotoxicity , a metabolic syndrome that occurs when fatty acids accumulate outside of adipose tissues , causing damage to the kidneys , liver , and heart .
As one of the preeminent diabetes scholars , he was uniquely poised to research treatments as well .
In 1978 , Unger and his colleagues provided evidence that administering the glucagon-suppressing hormone somatostatin normalized glucose levels in patients with type 1 diabetes .
Throughout the late 2000s , Unger also found that the hormone leptin was capable of suppressing glucagon in mice , @ @ @ @ @ @ @ lipotoxic effects by increasing the oxidation of errant fatty acids .
“ The fact that these animals don ’ t die and are restored to normal health despite a total lack of insulin is hard for many researchers and clinicians to believe , ” Unger said in a press release in 2008 .
Unger remained active as a physician and researcher until the months before he died , still at work on new experiments .
“ Every time I decide to retire , we stumble on something exciting , ” he shared in @ @ @ @ @ @ @ s too good to let go , so we ’ ll keep going as long as we have good ideas.
” He is survived by his brother , his wife Marlise , and their four children .

Roger Unger, who studied the hormonal underpinnings of diabetes for more than 60 years, died on August 22 at age 96. During his long tenure at the University of Texas Southwestern (UTSW) Medical Center that ended in July when he retired, he discovered the roles of the hormones glucagon and insulin in controlling blood sugar levels in the body.
Born in 1924 in New York, Unger attended Yale University and Columbia University during his medical training before spending the majority of his professional career at UTSW, where he was one of the longest-serving faculty members. He was the founding director of the Touchstone Diabetes Center, and his work helped elevate the institution to a world leader in the study and treatment of diabetes and related endocrine disorders. For his significant contributions to the field, he was awarded several honors, including the Banting Medal (1975), the Claude Bernard Memorial Medal (1980), the Fred Conrad Koch Award (1983), and the Rolf Luft Award in 2014 from the Karolinska Institute.
Roger Unger UT Southwestern Medical center
“Dr. Unger was a visionary endocrinologist who helped shape research and clinical practice in the field for more than 60 years,” Daniel Podolsky, president of UTSW, shared in an obituary. “His outstanding contributions in endocrinology and metabolism set the foundation for many of the important discoveries in these areas.”
Shortly after joining UTSW in 1956, Unger carried out experiments establishing glucagon as a true hormone involved in glucose production. Following this link, he next demonstrated the bihormonal nature of diabetes, showing that the high blood sugar characteristic of the disease stems not only from a lack of insulin, but also an overproduction of glucagon that increases glucose production. More recently, he had shown that blood glucose could not rise without abnormally high levels of glucagon. “Glucagon is the main culprit in diabetes, and if we can block its action, diabetes vanishes,” Unger said in a 2018 video about his work.
Throughout his career, he also focused on the interplay between obesity, diabetes, and metabolic syndrome, studying how combinations of risk factors led to the development of heart disease and type 2 diabetes. Unger was the first to introduce the concept of lipotoxicity, a metabolic syndrome that occurs when fatty acids accumulate outside of adipose tissues, causing damage to the kidneys, liver, and heart.
As one of the preeminent diabetes scholars, he was uniquely poised to research treatments as well. In 1978, Unger and his colleagues provided evidence that administering the glucagon-suppressing hormone somatostatin normalized glucose levels in patients with type 1 diabetes. Throughout the late 2000s, Unger also found that the hormone leptin was capable of suppressing glucagon in mice, thereby reversing high blood glucose and dampening lipotoxic effects by increasing the oxidation of errant fatty acids. “The fact that these animals don’t die and are restored to normal health despite a total lack of insulin is hard for many researchers and clinicians to believe,” Unger said in a press release in 2008.
Unger remained active as a physician and researcher until the months before he died, still at work on new experiments. “Every time I decide to retire, we stumble on something exciting,” he shared in the 2018 video. “It’s too good to let go, so we’ll keep going as long as we have good ideas.”
He is survived by his brother, his wife Marlise, and their four children.


thescientist--2020-09-08--Vector-Based Vaccines Come to the Fore in the COVID-19 Pandemic

Six vaccine candidates in clinical trials for COVID-19 employ viruses to deliver genetic cargo that , once inside our cells , instructs them to make SARS-CoV-2 protein .
This stimulates an immune response that ideally would protect recipients from future encounters with the actual virus .
Three candidates rely on weakened human adenoviruses to deliver the recipe for the spike protein of the pandemic coronavirus , while two use primate adenoviruses and one uses measles virus .
Most viral vaccines are based on attenuated or inactivated viruses .
An upside of using vectored vaccines is that they are easy and @ @ @ @ @ @ @ vector , for example , can be grown up in cells and used for various vaccines .
Once you make a viral vector , it is the same for all vaccines , says Florian Krammer , a vaccinologist at the Icahn School of Medicine at Mount Sinai .
“ It is just the genetic information in it that is different , ” he explains .
Once inside a cell , viral vectors hack into the same molecular system as SARS-CoV-2 and faithfully produce the spike protein in its three dimensions .
This resembles @ @ @ @ @ @ @ robust innate immune response , triggering inflammation and mustering B and T cells .
But the major downside to the human adenoviruses is that they circulate widely , causing the common cold , and some people harbor antibodies that will target the vaccine , making it ineffective .
CanSino reported on its Phase II trial this summer of its COVID-19 vaccine that uses adenovirus serotype 5 ( Ad5 ) .
The company noted that 266 of the 508 participants given the shot had high pre-existing immunity to the Ad5 vector , and that @ @ @ @ @ @ @ response to the vaccine , suggesting that the vaccine will not work so well in them .
“ The problem with adenovirus vectors is that different populations will have different levels of immunity , and different age groups will have different levels of immunity , ” says Nikolai Petrovsky , a vaccine researcher at Flinders University in Australia .
Also , with age , a person accumulates immunity to more serotypes .
“ Being older is associated with more chance to acquire Ad5 immunity , so those vaccines will be an issue [ @ @ @ @ @ @ @ explains .
Moreover , immunity against adenoviruses lasts for many years .
“ A lot of people have immunity to Ad5 and that impacts on how well the vaccine works , ” says Krammer .
In the US , around 40 percent of people have neutralizing antibodies to Ad5 .
As part of her work on an HIV vaccine , Hildegund Ertl of the Wistar Institute in Philadelphia previously collected serum in Africa to gauge resistance levels to this and other serotypes .
She found a high prevalence of Ad5 antibodies in sub-Saharan @ @ @ @ @ @ @ 90 percent .
A different group in 2012 reported that for children in northeast China , around one-quarter had moderate levels and 9 percent had high levels of Ad5 antibodies .
“ I don ’ t think anyone has done an extensive enough study to do a world map [ of seroprevalence ] , ” notes Ertl .
J & J ’ s Janssen is using a rarer adenovirus subtype , Ad26 , in its COVID-19 vaccine , reporting in July that it protects macaques against SARS-CoV-2 and in September that it protects @ @ @ @ @ @ @ Ad26 neutralizing antibodies are uncommon in Europe and the US , with perhaps 10–20 percent of people harboring antibodies .
They are more common elsewhere .
“ In sub-Saharan Africa , the rates are ranging from eighty to ninety percent , ” says Ertl .
Also critical is the level of antibodies in individuals , notes Dan Barouch , a vaccinologist at Beth Israel Deaconess Medical Center and Harvard Medical School .
For instance , there was no neutralizing of Ad26-based HIV and Ebola vaccines in more than 80,000 people in sub-Saharan Africa @ @ @ @ @ @ @ responses do not appear to be suppressed by the baseline Ad26 antibodies found in these populations , ” because the titres are low , Barouch writes in an email to The Scientist .
Barouch has long experience with Ad26-based vaccines and collaborates with J & J on their COVID-19 vaccine .
The Russian Sputnik V vaccine , approved despite no published data or Phase 3 trial results , starts with a shot of Ad26 vector followed by a booster with Ad5 , both of which carry the gene for the spike protein of @ @ @ @ @ @ @ viral vector vaccines , specifically , once you give the first shot , subsequent injections will be less efficacious because of antibodies against the vector .
Ertl says she has no idea of the proportion of the Russian population with Ad26 or Ad5 antibodies , and there seems to be little or no published data from countries that have expressed interested in this virus , such as Venezuela and the Philippines .
An alternative is look to our nearest relatives .
Chimp adenoviruses were the focus of vaccine interest by Ertl for HIV @ @ @ @ @ @ @ of Oxford for malaria .
“ About one percent of people have antibodies to the chimp adenovirus , probably because of cross reactivity , which is why we use it , ” explains Hill , referring to the COVID-19 vaccine candidate ChAdOx1 nCoV-19 , which has shown antibody and T cell responses in an early phase clinical trial .
This candidate , which also encodes the instructions for producing SARS-CoV-2 spike protein , is now in Phase 3 trials in the UK , US , South Africa , and Brazil and is to @ @ @ @ @ @ @ says Ertl , use of the attenuated chimp virus in a COVID-19 vaccine means it can not now be used for malaria , because those vaccinated for the coronavirus will have antibodies against the vector .
But there are other simian vectors .
In Italy , a Phase 1 trial of a COVID-19 vaccine with a gorilla adenovirus vector has begun recruiting healthy volunteers .
Ertl says that having multiple adenoviruses from different species is “ a good thing , because it broadens the range of diseases we could tackle.
” It could @ @ @ @ @ @ @ vaccines to be used in places where human adenovirus immunity is high .
Not everyone is enthusiastic about vector-based vaccines .
“ Their reactogenicity profile is not great , ” says Petrovsky , meaning they stimulate a strong immune response .
“ Even [ President Vladimir ] Putin commented that his daughter had a fever [ after taking Sputnik V ] .
Generally , fevers are a no-no for a vaccine.
” He says headache and fever have been relatively common in early results from vaccines based on viral vectors .
Some people @ @ @ @ @ @ @ , so extreme reactions can not be ruled out , he adds .
Petrovsky says children generally react more strongly to vaccines than adults do , and that could be a huge drawback in countries with young populations such as India .
“ With vectors you are always trying to find the sweet spot , ” says Petrovsky , which is their Achilles ’ s heel .
“ Too weak , and they don ’ t work .
Too strong , and they are too toxic.
” Petrovsky is involved in the development @ @ @ @ @ @ @ plus adjuvant that is in early clinical trials and was developed by his company Vaxine Pty in Australia .
So far , there is not much experience with vector-based vaccines on the market .
The European Medicines Agency granted market authorization in May for a new Ebola vaccine that consists of a prime shot with an Ad26 vector , and a booster with an attenuated poxvirus ( MVA ) .
An HIV vaccine trial based on Ertl ’ s research was to have started this fall , but has been delayed until next @ @ @ @ @ @ @ don ’ t have post-licensing experience , ” says Ertl , in relation to vector-based vaccines , “ but these things have been in multiple trials , so we have a reasonably good idea about what doses are tolerated and about safety concerns.
” In August , a trial in France and Belgium began recruiting volunteers to test a COVID-19 vaccine based on a replicating measles vaccine virus .
This so-called Schwartz strain was weakened in the 1960s by serial passaging on chicken cells .
The virus expresses the full-length spike protein of @ @ @ @ @ @ @ , say scientists at the Pasteur Institute in France who licensed the vector technology to Themis in Austria .
It was previously tested on mice for SARS and for MERS .
It was shown previously that pre-existing immunity to measles acquired by infection in the elderly or vaccination in young people did not dampen responses to a Chikungunya vaccine based on this same vector .
The measles vector “ goes into cells , then makes more measles vaccine .
It will come out again , infect more cells , but after a few @ @ @ @ @ @ @ scientist Christiane Gerke of the Pasteur Institute who is leading the COVID-19 vaccine trial .
That the measles strain replicates distinguishes it from the adenovirus vectors and could explain why pre-existing antibodies do not matter .
“ So long as measles antibodies at the start do not eliminate all of the vaccine , then the vaccine replicates itself , ” says Gerke .
The live nature of the measles vaccine strain means that it could not be given to immunocompromised individuals .
However , the Swartz strain has about 50 mutations and measles @ @ @ @ @ @ @ shackles and caused disease in healthy people .
“ It is a promising candidate , ” says Krammer , though a little behind the others .
The Pasteur Institute could not confirm whether volunteers had begun receiving the vaccine .
In June , Themis was acquired by Merck , a company with a significant vaccine portfolio .
Success with viral vectors has implications for vaccine development overall .
“ It took a very long time for viral vectors to end up on the market , which they did with the Ebola vaccines , @ @ @ @ @ @ @ I see it , this is going to speed up vaccine development in general.
” That is , as long as there is a successful outcome with a COVID-19 vaccine .
Any misstep by a regulator with one of these vaccines could retard the potential of vector-based vaccines for multiple diseases , says Krammer .

ABOVE: Colored transmission electron microscopic image of adenovirus virions
CDC /DR. G. WILLIAM GARY, JR.
Six vaccine candidates in clinical trials for COVID-19 employ viruses to deliver genetic cargo that, once inside our cells, instructs them to make SARS-CoV-2 protein. This stimulates an immune response that ideally would protect recipients from future encounters with the actual virus. Three candidates rely on weakened human adenoviruses to deliver the recipe for the spike protein of the pandemic coronavirus, while two use primate adenoviruses and one uses measles virus.
Most viral vaccines are based on attenuated or inactivated viruses. An upside of using vectored vaccines is that they are easy and relatively cheap to make. The adenovirus vector, for example, can be grown up in cells and used for various vaccines. Once you make a viral vector, it is the same for all vaccines, says Florian Krammer, a vaccinologist at the Icahn School of Medicine at Mount Sinai. “It is just the genetic information in it that is different,” he explains.
Once inside a cell, viral vectors hack into the same molecular system as SARS-CoV-2 and faithfully produce the spike protein in its three dimensions. This resembles a natural infection, which provokes a robust innate immune response, triggering inflammation and mustering B and T cells.
But the major downside to the human adenoviruses is that they circulate widely, causing the common cold, and some people harbor antibodies that will target the vaccine, making it ineffective.
Human adenovirus vectors
CanSino reported on its Phase II trial this summer of its COVID-19 vaccine that uses adenovirus serotype 5 (Ad5). The company noted that 266 of the 508 participants given the shot had high pre-existing immunity to the Ad5 vector, and that older participants had a significantly lower immune response to the vaccine, suggesting that the vaccine will not work so well in them.
With vectors you are always trying to find the sweet spot. Too weak, and they don’t work. Too strong, and they are too toxic. —Nikolai Petrovsky, Flinders University
“The problem with adenovirus vectors is that different populations will have different levels of immunity, and different age groups will have different levels of immunity,” says Nikolai Petrovsky, a vaccine researcher at Flinders University in Australia. Also, with age, a person accumulates immunity to more serotypes. “Being older is associated with more chance to acquire Ad5 immunity, so those vaccines will be an issue [with elderly people],” Krammer explains. Moreover, immunity against adenoviruses lasts for many years.
“A lot of people have immunity to Ad5 and that impacts on how well the vaccine works,” says Krammer. In the US, around 40 percent of people have neutralizing antibodies to Ad5. As part of her work on an HIV vaccine, Hildegund Ertl of the Wistar Institute in Philadelphia previously collected serum in Africa to gauge resistance levels to this and other serotypes. She found a high prevalence of Ad5 antibodies in sub-Saharan Africa and some West African countries—80 to 90 percent. A different group in 2012 reported that for children in northeast China, around one-quarter had moderate levels and 9 percent had high levels of Ad5 antibodies. “I don’t think anyone has done an extensive enough study to do a world map [of seroprevalence],” notes Ertl.
J&J’s Janssen is using a rarer adenovirus subtype, Ad26, in its COVID-19 vaccine, reporting in July that it protects macaques against SARS-CoV-2 and in September that it protects against severe clinical disease in hamsters. Ad26 neutralizing antibodies are uncommon in Europe and the US, with perhaps 10–20 percent of people harboring antibodies. They are more common elsewhere. “In sub-Saharan Africa, the rates are ranging from eighty to ninety percent,” says Ertl.
Also critical is the level of antibodies in individuals, notes Dan Barouch, a vaccinologist at Beth Israel Deaconess Medical Center and Harvard Medical School. For instance, there was no neutralizing of Ad26-based HIV and Ebola vaccines in more than 80,000 people in sub-Saharan Africa, he says. “Ad26 vaccine responses do not appear to be suppressed by the baseline Ad26 antibodies found in these populations,” because the titres are low, Barouch writes in an email to The Scientist. Barouch has long experience with Ad26-based vaccines and collaborates with J&J on their COVID-19 vaccine.
The Russian Sputnik V vaccine, approved despite no published data or Phase 3 trial results, starts with a shot of Ad26 vector followed by a booster with Ad5, both of which carry the gene for the spike protein of SARS-CoV-2. This circumvents a downside of viral vector vaccines, specifically, once you give the first shot, subsequent injections will be less efficacious because of antibodies against the vector. Ertl says she has no idea of the proportion of the Russian population with Ad26 or Ad5 antibodies, and there seems to be little or no published data from countries that have expressed interested in this virus, such as Venezuela and the Philippines.
Simian adenovirus vectors
An alternative is look to our nearest relatives. Chimp adenoviruses were the focus of vaccine interest by Ertl for HIV and by Adrian Hill at the University of Oxford for malaria. “About one percent of people have antibodies to the chimp adenovirus, probably because of cross reactivity, which is why we use it,” explains Hill, referring to the COVID-19 vaccine candidate ChAdOx1 nCoV-19, which has shown antibody and T cell responses in an early phase clinical trial. This candidate, which also encodes the instructions for producing SARS-CoV-2 spike protein, is now in Phase 3 trials in the UK, US, South Africa, and Brazil and is to be manufactured by AstraZeneca.
Unfortunately, says Ertl, use of the attenuated chimp virus in a COVID-19 vaccine means it cannot now be used for malaria, because those vaccinated for the coronavirus will have antibodies against the vector. But there are other simian vectors. In Italy, a Phase 1 trial of a COVID-19 vaccine with a gorilla adenovirus vector has begun recruiting healthy volunteers. Ertl says that having multiple adenoviruses from different species is “a good thing, because it broadens the range of diseases we could tackle.” It could also allow animal virus vectors for COVID-19 vaccines to be used in places where human adenovirus immunity is high.
Not everyone is enthusiastic about vector-based vaccines. “Their reactogenicity profile is not great,” says Petrovsky, meaning they stimulate a strong immune response. “Even [President Vladimir] Putin commented that his daughter had a fever [after taking Sputnik V]. Generally, fevers are a no-no for a vaccine.” He says headache and fever have been relatively common in early results from vaccines based on viral vectors. Some people are prone to having convulsions from fevers, so extreme reactions cannot be ruled out, he adds.
Petrovsky says children generally react more strongly to vaccines than adults do, and that could be a huge drawback in countries with young populations such as India. “With vectors you are always trying to find the sweet spot,” says Petrovsky, which is their Achilles’s heel. “Too weak, and they don’t work. Too strong, and they are too toxic.” Petrovsky is involved in the development of Covax-19, a recombinant protein–based vaccine plus adjuvant that is in early clinical trials and was developed by his company Vaxine Pty in Australia.
So far, there is not much experience with vector-based vaccines on the market. The European Medicines Agency granted market authorization in May for a new Ebola vaccine that consists of a prime shot with an Ad26 vector, and a booster with an attenuated poxvirus (MVA). An HIV vaccine trial based on Ertl’s research was to have started this fall, but has been delayed until next year due to COVID-19. “We don’t have post-licensing experience,” says Ertl, in relation to vector-based vaccines, “but these things have been in multiple trials, so we have a reasonably good idea about what doses are tolerated and about safety concerns.”
A measles vector
In August, a trial in France and Belgium began recruiting volunteers to test a COVID-19 vaccine based on a replicating measles vaccine virus. This so-called Schwartz strain was weakened in the 1960s by serial passaging on chicken cells. The virus expresses the full-length spike protein of SARS-CoV-2 and has been tested in mice, say scientists at the Pasteur Institute in France who licensed the vector technology to Themis in Austria. It was previously tested on mice for SARS and for MERS.
It was shown previously that pre-existing immunity to measles acquired by infection in the elderly or vaccination in young people did not dampen responses to a Chikungunya vaccine based on this same vector. The measles vector “goes into cells, then makes more measles vaccine. It will come out again, infect more cells, but after a few cycles it stops,” says vaccine scientist Christiane Gerke of the Pasteur Institute who is leading the COVID-19 vaccine trial. That the measles strain replicates distinguishes it from the adenovirus vectors and could explain why pre-existing antibodies do not matter. “So long as measles antibodies at the start do not eliminate all of the vaccine, then the vaccine replicates itself,” says Gerke.
The live nature of the measles vaccine strain means that it could not be given to immunocompromised individuals. However, the Swartz strain has about 50 mutations and measles vaccine strains have never escaped these attenuation shackles and caused disease in healthy people. “It is a promising candidate,” says Krammer, though a little behind the others. The Pasteur Institute could not confirm whether volunteers had begun receiving the vaccine. In June, Themis was acquired by Merck, a company with a significant vaccine portfolio.
Success with viral vectors has implications for vaccine development overall. “It took a very long time for viral vectors to end up on the market, which they did with the Ebola vaccines,” says Krammer. “The way I see it, this is going to speed up vaccine development in general.” That is, as long as there is a successful outcome with a COVID-19 vaccine. Any misstep by a regulator with one of these vaccines could retard the potential of vector-based vaccines for multiple diseases, says Krammer.


thescientist--2020-09-08--COVID-19 Symptoms in Kids Most Often Headache, Fever: App Data

A symptom-tracking app indicates that children experience different COVID-19 symptoms than adults , The Guardian reports .
While a persistent cough and a diminished sense of taste and smell are common among adults , the app has found , children with the virus most commonly experience symptoms such as headache , fatigue , and fever , among others .
Since the novel coronavirus emerged in late 2019 , scientists have been scrambling to understand its effects on human health .
In March , an international group of scientists and institutions announced the COVID Symptom Study to obtain data from patients @ @ @ @ @ @ @ , the app has received self-reported information on more than 4.1 million patients , helping to identify patterns based on demographics .
More than half of the 198 children in their system who tested positive for the virus experienced fatigue and headaches , according to The Guardian .
Fever occurred in around 50 percent .
Around one-third of the kids had sore throats , and a minority of children exhibited a skin rash or experienced diarrhea .
“ We need to start to telling people what are the key symptoms at different ages @ @ @ @ @ @ @ , cough , and lack of smell , ” Tim Spector , an epidemiologist at King ’ s College London and co-leader of the project , tells The Guardian .
He suggests that children showing these symptoms should be kept home from school , though not necessarily tested .
See “ COVID-19 Is ‘ Very Different ’ in Young Kids Versus Adults ” Sanjay Patel , a pediatric infectious disease doctor at Southampton Children ’ s Hospital in England , cautions that these symptoms are common among many childhood illnesses and could lead @ @ @ @ @ @ @ comes with risks .
“ The harms of that approach are very tangible , ” Patel tells The Guardian .
“ Many children would be missing a lot of school , and the majority of children being tested would still be negative.
” A recent New York Times article , unrelated to the app , comments on how it will be challenging in the coming months for parents to distinguish COVID-19 symptoms from those of the common cold .
“ This is not the year to be sending your kid to school sick @ @ @ @ @ @ @ with mild symptoms , which I know is crazy .
Because it ’ s really hard for parents , ” Adam Ratner , the director of pediatric infectious diseases at Hassenfeld Children ’ s Hospital in New York , tells the Times .
“ Sometimes mild symptoms are all we have to go on and kids are really good at shedding the virus , even if they don ’ t have symptoms .
”

ABOVE: © ISTOCK.COM, HALFPOINT
A symptom-tracking app indicates that children experience different COVID-19 symptoms than adults, The Guardian reports. While a persistent cough and a diminished sense of taste and smell are common among adults, the app has found, children with the virus most commonly experience symptoms such as headache, fatigue, and fever, among others.
Since the novel coronavirus emerged in late 2019, scientists have been scrambling to understand its effects on human health. In March, an international group of scientists and institutions announced the COVID Symptom Study to obtain data from patients with COVID-19. According to its website, the app has received self-reported information on more than 4.1 million patients, helping to identify patterns based on demographics.
More than half of the 198 children in their system who tested positive for the virus experienced fatigue and headaches, according to The Guardian. Fever occurred in around 50 percent. Around one-third of the kids had sore throats, and a minority of children exhibited a skin rash or experienced diarrhea.
“We need to start to telling people what are the key symptoms at different ages rather than this blanket obsession with fever, cough, and lack of smell,” Tim Spector, an epidemiologist at King’s College London and co-leader of the project, tells The Guardian. He suggests that children showing these symptoms should be kept home from school, though not necessarily tested.
Sanjay Patel, a pediatric infectious disease doctor at Southampton Children’s Hospital in England, cautions that these symptoms are common among many childhood illnesses and could lead parents to unduly quarantine children, which comes with risks. “The harms of that approach are very tangible,” Patel tells The Guardian. “Many children would be missing a lot of school, and the majority of children being tested would still be negative.”
A recent New York Times article, unrelated to the app, comments on how it will be challenging in the coming months for parents to distinguish COVID-19 symptoms from those of the common cold.
“This is not the year to be sending your kid to school sick, even a little bit, even with mild symptoms, which I know is crazy. Because it’s really hard for parents,” Adam Ratner, the director of pediatric infectious diseases at Hassenfeld Children’s Hospital in New York, tells the Times. “Sometimes mild symptoms are all we have to go on and kids are really good at shedding the virus, even if they don’t have symptoms.”


thescientist--2020-09-09--Immunotherapy Combo Reduces Solid Tumors in Mice

ABOVE : Researchers used engineered viruses to force the production of the CD19 protein ( in purple ) on the surface of solid tumor cells in a dish .
CITY OF HOPE Researchers have been working in recent years to apply the successes of CAR T cell immunotherapy treatments to solid tumors .
But breast , liver , brain , and other solid cancers have been less amenable to the approach than blood-based cancers have been .
Now , scientists are looking to piggyback CAR T cells with other promising immunotherapies , such as oncolytic viruses , which preferentially infect @ @ @ @ @ @ @ positive benefits to other malignancies .
A study published on September 2 in Science Translational Medicine details the collective strength of these two immunotherapies to eliminate solid cancers using a protein marker called CD19 , which is targeted in CAR T therapies for liquid cancers .
In both human cancer cell cultures and mouse models , solid tumor cells exposed to an oncolytic virus were forced to express the gene for CD19 , a tumor-specific marker that was then targeted subsequently by CAR T cells .
CAR stands for chimeric antigen receptor , @ @ @ @ @ @ @ cells to a complimentary antigen specific to cancer cells .
These cancer cells died at much higher rates than in controls .
In addition , CAR T cells prompted the activation of native T cells in mice , initiating a broader immune response that protected the animals from relapse .
“ It ’ s not just the CAR T cells doing something , and it ’ s not just the oncolytic virus , ” says Anthony Park , a postdoc at City of Hope outside of Los Angeles and the lead author of @ @ @ @ @ @ @ immune response , “ we ’ re actually bringing three components together.
” Oncolytic viruses are bioengineered , benign viruses created specifically to infiltrate and replicate within cancer cells .
If scientists modify an oncolytic virus to carry a particular gene , it can function as a Trojan horse , smuggling the gene inside and forcing infected cells to express the gene for a desired surface protein that flags them as cancerous to T cells .
The authors chose CD19 as the cancer flag for the virus because of its demonstrated ability to @ @ @ @ @ @ @ for leukemia and lymphoma , which naturally present the marker .
Solid cancers are more difficult to treat with CAR T cells than liquid cancers for a number of reasons .
Tumors are difficult to penetrate , and once inside , immune cells face a toxic , immunosuppressive environment .
In addition , solid tumors are heterogeneous , meaning that each cell has its own mosaic of surface proteins , many of which are shared with healthy cells .
In contrast , CD19 doesn ’ t typically appear outside of blood malignancies .
@ @ @ @ @ @ @ a unique antigen common to all cells within solid tumors .
Saul Priceman , a hematologist at City of Hope and the senior author on the study , says he realized that if the team could find a way to make solid tumors produce CD19 , these cancers could then be targeted by CAR T cells .
So his group engineered an oncolytic vaccinia virus carrying a payload of CD19 .
“ We thought , ‘ If it works for blood cancers , why can ’ t we make it work for solid @ @ @ @ @ @ @ Scientist .
“ And that ’ s what we set out to do.
” See “ The Next Frontier of CAR T-Cell Therapy : Solid Tumors ” The team began with in vitro studies using a variety of human cancer cells in culture .
First , they showed that their modified vaccinia virus could in fact deliver the CD19 gene into tumor cells , leading to the presence of the protein on their surfaces .
As the viruses replicated , some tumor cells burst , spilling the virus onto nearby cells that escaped @ @ @ @ @ @ @ 24 hours , nearly all the cells had been successfully modified .
Ten days later , the team added CAR T cells designed to destroy cells bearing CD19 to the culture .
Together , the deaths caused by the virus and the subsequent attack by T cells resulted in a loss of between 60 percent and 70 percent of tumor cells over the next few days .
“ The whole idea that you can turn a solid tumor into a quasi–B cell [ liquid cancer ] by introducing a CD19 antigen was clever @ @ @ @ @ @ @ Rezvani , a transplant immunologist at the MD Anderson Cancer Center who was not involved in the study .
“ The experiments were very well done , very convincing.
” Next , Park and his colleagues applied their combined immunotherapy to several mouse models , focusing on both the efficacy of the treatment and how best to deliver it .
They began with an immunosuppressed model to test the therapy on human breast cancer tumor cells and human T cells in a pared down immune environment .
Ten days after injecting the virus @ @ @ @ @ @ @ 70 percent of the cells harbored CD19 .
Mice that received both the virus and T cells showed marked tumor regression compared to mice that received mock T cells .
The second model , known as a syngeneic , immunocompetent mouse model , used mouse cancer cells and immune cells rather than human cells , but allowed the team to study the full suite of immune cells involved in fighting cancer .
Among mice that received only the virus , 22 percent recovered from the cancer due to virus-induced cell death alone , @ @ @ @ @ @ @ infections of healthy cells .
When combined with CAR T cells , the number of mice experiencing complete tumor regression jumped to roughly 60 percent .
Lastly , Park and his colleagues used an immunocompetent model to study an emerging question in the field : how best to deliver these therapies .
Treatments for liquid cancers are administered by IV , but debate exists over whether a systemic or local injection would be best for solid tumors .
Both the viruses and the T cells might benefit from being injected directly , as @ @ @ @ @ @ @ at higher viral concentrations ( greater than 105 plaque-forming units per mouse ) .
However , many solid cancers metastasize , making them difficult to access .
Trying out various injection protocols , the researchers found that mice with metastatic tumors that received a regional injection of viruses and T cells into the peritoneal lining surrounding the main body cavity had a lower tumor burden and generally survived longer than controls did .
These findings suggest that oncolytic viruses may be amenable to IV drips ; currently , the only oncolytic virus therapy @ @ @ @ @ @ @ Administration relies on direct injection into a tumor .
“ Our future [ research focus ] is whether we can give this virus systemically and safely so those viruses can seek out all the tumors wherever they may be in the body , ” Priceman tells The Scientist .
Andrea Schmidts , a CAR specialist at Harvard Medical School who was not involved in the study , says she found the authors ’ rigorous use of mouse models and their testing of different delivery methods “ a very important quality marker ” of @ @ @ @ @ @ @ having both these models is very robust , ” Schmidts says .
The team has already begun designing a Phase I clinical trial , which could begin in the next year or two .
Priceman and Park say the future of cancer treatment lies in these combinatorial therapies , and they don ’ t necessarily intend to stop at only two different methods .
For example , they ’ re currently considering combining their new therapy with checkpoint inhibitor drugs that unmask efforts by tumors to cloak themselves from surrounding immune cells .
@ @ @ @ @ @ @ says , “ there are hints that blocking checkpoints might amplify the therapeutic response .
”

ABOVE: Researchers used engineered viruses to force the production of the CD19 protein (in purple) on the surface of solid tumor cells in a dish.
CITY OF HOPE
Researchers have been working in recent years to apply the successes of CAR T cell immunotherapy treatments to solid tumors. But breast, liver, brain, and other solid cancers have been less amenable to the approach than blood-based cancers have been. Now, scientists are looking to piggyback CAR T cells with other promising immunotherapies, such as oncolytic viruses, which preferentially infect cancerous cells, to bring the same positive benefits to other malignancies.
A study published on September 2 in Science Translational Medicine details the collective strength of these two immunotherapies to eliminate solid cancers using a protein marker called CD19, which is targeted in CAR T therapies for liquid cancers.
In both human cancer cell cultures and mouse models, solid tumor cells exposed to an oncolytic virus were forced to express the gene for CD19, a tumor-specific marker that was then targeted subsequently by CAR T cells. CAR stands for chimeric antigen receptor, a homing beacon engineered to lead T cells to a complimentary antigen specific to cancer cells. These cancer cells died at much higher rates than in controls. In addition, CAR T cells prompted the activation of native T cells in mice, initiating a broader immune response that protected the animals from relapse. “It’s not just the CAR T cells doing something, and it’s not just the oncolytic virus,” says Anthony Park, a postdoc at City of Hope outside of Los Angeles and the lead author of the study. By engaging the endogenous immune response, “we’re actually bringing three components together.”
Oncolytic viruses are bioengineered, benign viruses created specifically to infiltrate and replicate within cancer cells. If scientists modify an oncolytic virus to carry a particular gene, it can function as a Trojan horse, smuggling the gene inside and forcing infected cells to express the gene for a desired surface protein that flags them as cancerous to T cells.
The authors chose CD19 as the cancer flag for the virus because of its demonstrated ability to attract CAR T cells in approved treatments for leukemia and lymphoma, which naturally present the marker.
Solid cancers are more difficult to treat with CAR T cells than liquid cancers for a number of reasons. Tumors are difficult to penetrate, and once inside, immune cells face a toxic, immunosuppressive environment. In addition, solid tumors are heterogeneous, meaning that each cell has its own mosaic of surface proteins, many of which are shared with healthy cells. In contrast, CD19 doesn’t typically appear outside of blood malignancies.
So far, scientists have not identified a unique antigen common to all cells within solid tumors.
Saul Priceman, a tumor immunologist at City of Hope and the senior author on the study, says he realized that if the team could find a way to make solid tumors produce CD19, these cancers could then be targeted by CAR T cells. So his group engineered an oncolytic vaccinia virus carrying a payload of CD19. “We thought, ‘If it works for blood cancers, why can’t we make it work for solid tumors?’” Priceman tells The Scientist. “And that’s what we set out to do.”
Modified CAR T cells target solid tumor cells bearing the CD19 protein in vitro. city of hope
The team began with in vitro studies using a variety of human cancer cells in culture. First, they showed that their modified vaccinia virus could in fact deliver the CD19 gene into tumor cells, leading to the presence of the protein on their surfaces. As the viruses replicated, some tumor cells burst, spilling the virus onto nearby cells that escaped the first wave of infection. After 24 hours, nearly all the cells had been successfully modified.
Ten days later, the team added CAR T cells designed to destroy cells bearing CD19 to the culture. Together, the deaths caused by the virus and the subsequent attack by T cells resulted in a loss of between 60 percent and 70 percent of tumor cells over the next few days.
“The whole idea that you can turn a solid tumor into a quasi–B cell [liquid cancer] by introducing a CD19 antigen was clever and really novel,” says Katy Rezvani, a transplant immunologist at the MD Anderson Cancer Center who was not involved in the study. “The experiments were very well done, very convincing.”
Next, Park and his colleagues applied their combined immunotherapy to several mouse models, focusing on both the efficacy of the treatment and how best to deliver it.
They began with an immunosuppressed model to test the therapy on human breast cancer tumor cells and human T cells in a pared down immune environment. Ten days after injecting the virus directly into a subcutaneous tumor, roughly 70 percent of the cells harbored CD19. Mice that received both the virus and T cells showed marked tumor regression compared to mice that received mock T cells.
See “Tactical Maneuvers”
The second model, known as a syngeneic, immunocompetent mouse model, used mouse cancer cells and immune cells rather than human cells, but allowed the team to study the full suite of immune cells involved in fighting cancer.
Among mice that received only the virus, 22 percent recovered from the cancer due to virus-induced cell death alone, and the authors noted very few off-target infections of healthy cells. When combined with CAR T cells, the number of mice experiencing complete tumor regression jumped to roughly 60 percent.
Lastly, Park and his colleagues used an immunocompetent model to study an emerging question in the field: how best to deliver these therapies. Treatments for liquid cancers are administered by IV, but debate exists over whether a systemic or local injection would be best for solid tumors. Both the viruses and the T cells might benefit from being injected directly, as the results in the study were strongest at higher viral concentrations (greater than 105 plaque-forming units per mouse). However, many solid cancers metastasize, making them difficult to access.
Trying out various injection protocols, the researchers found that mice with metastatic tumors that received a regional injection of viruses and T cells into the peritoneal lining surrounding the main body cavity had a lower tumor burden and generally survived longer than controls did. These findings suggest that oncolytic viruses may be amenable to IV drips; currently, the only oncolytic virus therapy approved by the US Food and Drug Administration relies on direct injection into a tumor. “Our future [research focus] is whether we can give this virus systemically and safely so those viruses can seek out all the tumors wherever they may be in the body,” Priceman tells The Scientist.
Andrea Schmidts, a CAR specialist at Harvard Medical School who was not involved in the study, says she found the authors’ rigorous use of mouse models and their testing of different delivery methods “a very important quality marker” of the study. “The combination of having both these models is very robust,” Schmidts says.
The team has already begun designing a Phase I clinical trial, which could begin in the next year or two. Priceman and Park say the future of cancer treatment lies in these combinatorial therapies, and they don’t necessarily intend to stop at only two different methods. For example, they’re currently considering combining their new therapy with checkpoint inhibitor drugs that unmask efforts by tumors to cloak themselves from surrounding immune cells.
Based on their preliminary work, Priceman says, “there are hints that blocking checkpoints might amplify the therapeutic response.”