Inhibition of proliferative and plaque-forming cell responses by human bone-marrow-derived lymphocytes from peripheral blood by antisera to the p23, 30 antigen.

A recently described technique for the polyclonal induction of plaque-forming cells from human bone-marrow derived (B) lymphocytes of peripheral blood has been used to assess the role of a human Ia-like antigen (p23,30) in differentiation of human B cells. In particular, the effects of antisera to p23,30 on the plaque-forming cells and proliferative responses of human B cells stimulated by pokeweed mitogen or soluble products of activated human thymus-derived lymphocytes (T cells) have been examined. Antisera to p23,30 eliminated the development of plaque-forming cells induced by both T cell products and pokeweed mitogen. While these antisera also abrogated B cell proliferation induced by T cell supernatants, the proliferative response generated by pokeweed mitogen was only partially reduced. It was also determined that while the p23,30 antigen continues to be expressed on fully differentiated plaque-forming cells, antisera to this determinant exert inhibitory effects on B cell differentiation only when present during the early stages of B cell cultures. These results lend further support to the analogy between p23,30 and murine Ia antigens. Moreover, they demonstrate a major role for this antigen in the early events involved in human B cell differentiation into antibody-forming cells.