[Triggering of human peripheral blood B cells by supernatants of activated T cells: the role of Ia-like determinants].

Human peripheral blood B lymphocytes, isolated by Sephadex G-200 anti-Fab column chromatography, were non specifically induced by either pokeweed mitogen (PWM) or soluble products of antigen stimulated T cells, to differenciate into plaque directed against human Ia-like antigens (anti-p 23-30) inhibited the differenciation of B cells into antibody forming cells. Thus, while PWM induced proliferation was only mildly reduced by anti-p 23-30, the PWM induced PFC response was totally abrogated. Conversely, the antiserum abolished both the proliferative and the PFC responses generated by products of activated T cells. Using both Ouchterlony plates and co-precipitation techniques, we were unable to detect p 23-30 molecules on the active products present in the T cells supernatants. These data suggest that the inhibitory effects are secondary to interaction of the antiserum with B cells determinants.