Potentiation of the stimulatory capacity of pokeweed mitogen via its binding to autologous erythrocytes.

The effect of human erythrocytes (E) on blastogenesis and immunoglobulin (Ig) production induced by pokeweed mitogen (PWM) in cultures of human peripheral blood mononuclear cells (PBMC) was investigated. The stimulation of PBMC with PWM was markedly enhanced in the presence of E, and PWM bound to E, followed by thorough washing (E-PWM), was even more effective in inducing blast cell formation and Ig production. Blast cell responses after stimulation with E-PWM were on average two times higher than those seen after stimulation with comparable dilutions of fluid-phase PWM. The PWM that remained in solution after incubation with E (Sup E-PWM) had little mitogenic capacity and inhibited the blast cell response induced by fluid-phase PWM. Transwell culture experiments demonstrated that the enhancement of the blast cell response of PBMC by E-PWM could be induced by PWM that was released from E-PWM, whereas the enhancement of Ig production was found to be dependent on the presence of PWM on E. Both for blast cell formation and Ig production, it was found that the enhanced stimulation with E-PWM depended on the presence of monocytes.