We have constructed recombinant baculoviruses and vaccinia viruses containing 
cloned DNA, encoding either the envelope protein alone or all of the structural 
proteins (core, membrane and envelope) of louping ill virus. Glycosylated viral 
envelope protein, presented both inside and on the surface of insect and 
mammalian cells, was expressed by all four recombinant viruses. Differences in 
antigenic presentation of the envelope protein were observed between the 
envelope protein and structural protein constructs as well as between the insect 
and mammalian cell expression systems. Despite the expression of epitopes known 
to elicit neutralizing and protective antibodies when present in authentic 
antigen, the recombinant envelope protein expressed by either vector failed to 
induce, in mice or rabbits, either neutralizing or protective antibodies against 
louping ill virus.