Analysis of the human Ig isotype response to lactoferrin binding protein Afrom Neisseria meningitidis

An effective vaccine for serogroup B meningococci has yet to be developed a nd attention has turned to subcapsular antigens of the meningococcus as pos sible vaccine candidates. Iron binding proteins are being studied, with mos t interest focused on the transferrin binding proteins (TbpA and TbpB) and the ferric binding protein (FbpA). This study describes the purification of lactoferrin binding protein A (LbpA) from two meningococcal strains and as sesses the human isotype-specific serum antibody response to these proteins in patients with proven meningococcal disease due to a range of phenotypes . Overall, fewer than 50% of sera contained IgG that recognised LbpA isolat ed from either strain and this antibody response was not uniform between th e two proteins. There was some evidence that the antibody response varied b etween meningococcal phenotypes. This study demonstrates that LbpA does not induce a highly cross-reactive antibody response, indicating that it is un likely to be an effective vaccine antigen. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights re served.