Immune response to native NadA from Neisseria meningitidis and its expression in clinical isolates in Brazil

ABSTRACT

A mAb against the NadA protein from Neisseria meningitidis strain 3006 (serosubtype B 2b P1.2 P5.2,8) demonstrated strong bactericidal activity against Brazilian epidemic serogroup B strain N44/89 (B 4,7 P1.19,15 P5.5,7) and a serogroup C strain, IMC 2135 (C 2a P1.5,2), but not against another serogroup C strain, N1002/90 (C 2b P1.3 P5.8). The immunogenicity of native NadA in an outer-membrane vesicle (OMV) preparation was also tested. Serum from mice immunized with OMV from serogroup B strain N44/89, which contains the NadA protein, showed bactericidal activity against serogroup B and C strains possessing NadA. In dot-blot analysis of 100 serogroup B and 100 serogroup C isolates from Brazilian patients, the mAb to NadA recognized about 60% of the samples from both serogroups. The molecular mass of the NadA protein from strain N44/89 determined by mass spectrometry was 37 971 Da and the peptide sequences were identical to those of NadA from N. meningitidis strain MC58.