Immunisation against bacterial meningitis.

The vaccine potential of different surface antigens of encapsulated bacteria is considered. It is concluded that only the capsular polysaccharides provide good protection. Polysaccharides are, however, thymus-independent antigens and the antibody response is strongly influenced by the age of the recipient and his naturally acquired immunity. For a long-lasting immunity the induction of mainly IgG antibodies is essential. Such a response can easily be induced by conjugates in which the polysaccharides have been attached to thymus-dependent carriers.