The physico-chemical characterization of NadADelta(351-405), a recombinant 
protein discovered by reverse vaccinology, component of a candidate vaccine 
against Neisseria meningitidis serotype B is presented. Analytical methods like 
mass spectrometry, electrophoresis, optical spectroscopy and SEC-MALLS have been 
applied to unveil the structure of NadADelta(351-405), and to evaluate 
Product-Related Substances. Moreover, analysis of the protein after intentional 
denaturation has been applied in order to challenge the chosen methods and to 
determine their appropriateness and specificity. All the obtained results were 
inserted in a model allowing in-depth understanding of the antigen 
NadADelta(351-405): it is present in solution as a homo-trimer, retaining a high 
percentage of alpha-helix secondary structure, and able to reassemble from 
monomeric subunits after thermal denaturation; this structural organization is 
consistent with that foreseen for MenB NadA (Neisseria Adhesin A). The 
analytical data sets produced during process development for clinical phases 
I-III material confirm product quality and manufacturing consistency.