Phorbol myristate acetate inhibits immunoglobulin synthesis by human peripheral blood lymphocytes

Phorbol myristate acetate (PMA), a known lymphocyte mitogen, has been shown to inhibit immunoglobulin synthesis by human peripheral blood lymphocytes. This effect occurs with low concentrations of the agent and following only 12 h contact with the lymphocytes. PMA was also capable of preventing pokeweed mitogen stimulation of lymphocytes. These experiments suggest that PMA prevents the complete differentiation of B-cells into plasma cells capable of secreting immunoglobulin.