Spleen cells from animals tolerant to a thymus-dependent antigen can be activated by lipopolysaccharide to synthesize antibodies against the tolerogen.
Immunological tolerance was induced in adult mice by the injection of 5 mg of deaggregated hapten-protein conjugate. The tolerant state was confirmed 4-19 days later by the failure of such animals to mount an immune response against an aggregated form of the same thymus-dependent hapten-protein conjugate as well as by the inability of spleen cells from tolerant animals to respond to a thymus-independent hapten-carrier conjugate. Even though the animals were fully tolerant, their spleen cells were activated by lipopolysaccharide (LPS) in vitro to produce normal numbers of plaque-forming cells against the hapten. The finding that spleen cells from tolerant animals could be activated by LPS into synthesis of antibodies against the tolerogen indicates that tolerance to thymus-dependent antigens does not affect B cells, but presumably only T cells. It is suggested that the only stringent test for the existence of B-cell tolerance is the inability of polyclonal B-cell activators to activate antibody synthesis against the tolerogen. The findings make it unlikely that B-cell tolerance to autologous thymus-dependent antigens exists and further indicate that such antigens cannot deliver activating or tolerogenic signals to B cells, although they are competent to combine with and block the Ig receptors.
D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D001402:B-Lymphocytes / Q000276:immunology; D004926:Escherichia coli; D006241:Haptens; D007108:Immune Tolerance; D008070:Lipopolysaccharides / Q000276:immunology*; D051379:Mice; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D013154:Spleen / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
D006241:Haptens; D008070:Lipopolysaccharides; D011135:Polysaccharides, Bacterial