[Gonococcal surface antigens and their significance for serotyping and vaccines]

Outer membrane components of Neisseria gonorrhoeae play an important role in the initial steps of infection. Precise knowledge about the surface antigens is needed for the development of a serotyping system and of a vaccine against local and systemic gonorrhea. Structure, antigenicity, and function of the best-known membrane components, i.e., lipopolysaccharide, protein I, protein II, protein III, and pili, are discussed. Lipopolysaccharide is a strong immunogen and induces bactericidal antibodies, but is unsuitable for use as a vaccine because of its toxicity. Protein I and protein III are stable proteins, not subject to antigenic variation. Antibodies against protein I, which are able to kill N. gonorrhoeae, are detectable in the serum of patients with disseminated gonococcal infection. Protein II and pili are highly variable antigens with constant, very slightly immunogenic regions. To interrupt the pathomechanism of gonococcal infection at different stages, future vaccines should contain more than one surface antigen.