Antigenic cross-reactivity between outer membrane proteins of Neisseria meningitidis and commensal Neisseria species

Two mouse sera against outer membrane proteins from a pathogenic Neisseria meningitidis strain and a commensal N. lactumica strain and two human sera from patients recovering From meningococcal meningitis were used to identif y antigens common to pathogenic and commensal Neisseia species. Two major a ntigens of 55 kDa and 32 kDa, present in all N meningitidis and N lactamica strains tested, were demonstrable with all the sera used; the 55-kDa prote in was iron-regulated. Demonstration of other common antigens was dependent on the serum used: a 65-kDa antigen was visualised with the human and the mouse anti-N;. lactamica sera; a 37-kDa antigen identified as the meningoco ccal ferric binding protein (FbpA) was only detected with the mouse sera, a nd two antigens of 83 kDa and 15 kDa were only shown with the mouse anti-N. meningitidis serum. The results demonstrate the existence of several outer membrane antigens common to N. lactamica and N meningitidis. strains, in a greement with the hypothesis that natural immunity against meningitis is pa rtially acquired through colonisation by commensal species. and open new pe rspectives for the design of vaccine formulations and the development of st rategies for vaccination against meningitis. (C) 2000 Federation of Europea n Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.