Antigen-binding lymphocytes in guinea pigs. I.B cell expansion to the monovalent antigen L-tyrosine-p-azophenyl trimethylammonium (tyr(TMA)) in the absence of antibody production.

The monofunctional antigen L-tyrosine-p-azophenyltrimethylammonium chloride, tyr(TMA), and the polyfunctional antigen, TMA-human gamma-globulin (TMA-HGG), were used to investigate the antigen structural requirements necessary for clonal proliferation of B cells. This clonal expansion was characterized with respect to receptor immunoglobulin class and affinity maturation. Antigen-binding analysis revealed that inoculation of tyr(TMA), although only of m.w. 344, triggers clonal expansion of B lymphocytes 9-fold in the absence of any apparent antibody production. There does not appear to be any maturation with respect to antibody class since greater than 90% of the tyr(TMA)-specific B cells bear the micron receptor in the nonimmune and immune state. However, the average avidity of the B cells for this antigen increases with time after immunization. In contrast, immunization with TMA-HGG results in an 18-fold increase in B lymphocytes with significant amounts of anti-TMA antibody production. With time after immunization, both maturation of average avidity and class of Ig receptor (micron leads to gamma shift) occur. These findings indicate that the functionally T cell-specific antigen tyr(TMA) can trigger clonal B cell expansion and affinity maturation at the receptor level in the absence of detectable antibody production.