CURRENT STATUS OF MENINGOCOCCAL GROUP-B VACCINE CANDIDATES - CAPSULAROR NONCAPSULAR

Meningococcal meningitis is a severe, life-threatening infection for w hich no adequate vaccine exists. Current vaccines, based on the group- specific capsular polysaccharides, provide short-term protection in ad ults against serogroups A and C but are ineffective in infants and do not induce protection against group B strains, the predominant cause o f infection in western countries, because the purified serogroup B pol ysaccharide fails to elicit human bactericidal antibodies. Because of the poor immunogenicity of group B capsular polysaccharide, different noncapsular antigens have been considered for inclusion in a vaccine a gainst this serogroup: outer membrane proteins, lipooligosaccharides, iron-regulated proteins, Lip, pili, CtrA, and the immunoglobulin A pro teases. Alternatively, attempts to increase the immunogenicity of the capsular polysaccharide have been made by using noncovalent complexes with outer membrane proteins, chemical modifications, and structural a nalogs. Here, we review the strategies employed for the development of a vaccine for Neisseria meningitidis serogroup B; the difficulties as sociated with the different approaches are discussed.