Evaluation of cross-reactive antigens as determinants of cross-bactericidal activity in pathogenic and commensal Neisseria

Several antisera raised against outer membane vesicles obtained from invasi ve and carrier Neisseria in meningitidis strains and commensal Neisseria an d Moraxella catharralis species were assayed to test cross-bactericidal act ivity on Neisseria meningitidis strains. Results demonstrate that, despite the wide antigenic cross-reactivity previously shown by Western-blotting fo r the major outer membrane antigenic proteins of all Neisseria species, com plement mediated killing shows very variable patterns that can not be predi cted on the basis of antigenic cross-reactivity. Results of antibody tritat ions on homologous and heterologous strains, isotyping,: and bactericidal a ctivity of sera raised against denatured purified outer-membrane vesicle pr oteins, suggest that the responsibility for most of the bactericidal activi ty of the sera must be conformational and/or shared epitopes not detectable by Western-blotting, (C) 2001 Elsevier Science Ltd. All rights reserved.