Mouse immune response to meningococcal antigens.

The mouse immune response against Neisseria meningitidis was studied by using an extract from group Y (Slaterus) known to contain protein antigens common to other meningococci. By using a solid-phase radioimmunoassay, high titers of specific IgM and IgG class antibodies were measured which lasted over 2 months after immunization. These antibodies cross-reacted with similar extracts from other meningococci groups. Bactericidal antibodies directed against protein antigens were also elicited after immunization and they belonged to IgM, IgG2a, and IgG2b isotypes. Cellular immunity, expressed as delayed type hypersensitivity under the conditions tested, could be detected neither in homologous nor heterologous reactions.