Activation of human B lymphocytes. VII. The regulatory effect of cyclic adenosine monophosphate on human B cell activation

Cyclic adenosine monophosphate (cAMP) has been demonstrated to play an integral role in the regulation of B cell activation. By employing a plaque-forming cell (PFC) assay for polyclonal activation of human B lymphocytes, it was demonstrated that dibutyryl cyclic adenosine monophosphate (DB-cAMP) markedly increased the PFC response of pokeweed mitogen (PWM)-stimulated lymphocytes. Inducers of intracellular cAMP effected a comparable enhancement. Co-cultures of fresh lymphocytes with autologous T cells which had been pre-incubated with DB-cAMP produced an enhancement of B cell activation by a selective effect on the T cells. The mechanism of action of this enhancement of the B cell response is most likely a relative increase in helper T cell function resulting from a selective inhibition of suppressor T cells.