Generation of B suppressor cells by phytohaemagglutinin.

Activation by phytohaemagglutinin-P (PHA-P) of B cells from peripheral blood of healthy subjects generated B suppressor cells which inhibited allogeneic mixed lymphocyte reactions (MLR) and PHA-induced DNA synthesis. Their action was direct, that is, not mediated through the induction of T suppressor cells. The finding that B cells can be induced by PHA to become highly effective suppressor cells may have important clinical and experimental implications.