title: T-cell modulation of the murine antibody response to Neisseria meningitidis group A capsular polysaccharide.
abstract: T-cell modulation of the antibody response of BALB/c mice to group A meningococcal capsular polysaccharide (PS) was examined by using an enzyme-linked immunosorbent assay. An optimal dose (5 micrograms) of antigen induced an immunoglobulin M (IgM) response of short duration; no IgG or IgA antibody could be detected. The capacity to produce serum antibody begins at about 3 weeks of age. Concanavalin A (ConA) inhibited the magnitude of the response by 40 to 60% when given at the time of immunization; it enhanced the response two- to eightfold when given 2 days after PS. T-cell-mediated suppression could be transferred to naive mice by injection of spleen cells from low-dose-primed mice. A secondary antibody response could be induced by immunization with live meningococci. Here, the IgM response was 8- to 10-fold greater than that of mice given an optimal dose of PS; IgG antibody against group A PS increased 1 week after immunization to levels that were 100- to 1,000-fold greater than those of mice immunized with PS. The antibody response could not be augmented by multiple injections of PS; suppression occurred after low-dose priming or hyperimmunization with PS. These studies indicate that the antibody response to PS is not completely T-cell independent; rather, it is inhibited and amplified by T cells.
mesh_terms: D000375:Aging; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis* / Q000502:physiology; D000961:Antilymphocyte Serum / Q000494:pharmacology; D003208:Concanavalin A; D004306:Dose-Response Relationship, Immunologic; D007116:Immunization, Passive; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000502:physiology; D007156:Immunologic Memory; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D009345:Neisseria meningitidis / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000494:pharmacology*; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000961:Antilymphocyte Serum; D007075:Immunoglobulin M; D011135:Polysaccharides, Bacterial; C043226:meningococcal group A polysaccharide; D003208:Concanavalin A