Antibodies to outer membrane protein — macromolecular complex (OMP-MC) are bactericidal for serum-resistant gonococci

The complement-dependent bactericidal activities of rabbit polyclonal and mouse monoclonal anti-OMP-MC antibodies were evaluated against homologous and heterologous strains of serum-resistant gonococci. Rabbit anti-OMP-MC promoted killing of homologous FA 19 organisms and two of three heterologous strains at dilutions up to 1:200; mouse IgM monoclonal promoted killing of homologous organisms. Bactericidal activities were not influenced by the presence of proteins II. Partial proteolysis of OMP-MC indicated that antibodies in bactericidal sera bound to papain-sensitive portions of the complex that represent <25% of the mass of OMP-MC.