Induction of human in vitro IgE synthesis via stimulation by anti-CD3 antibody.

Mitogens such as pokeweed mitogen, Staphylococcus aureus Cowan I, concanavalin A and phytohemagglutinin and monoclonal anti-CD antibodies were examined for their capacity to induce IgE synthesis by peripheral blood leukocytes obtained from both atopic and nonatopic individuals. While lectins failed to induce IgE synthesis, monoclonal anti-CD3 antibodies were very potent stimuli for the induction of human in vitro IgE synthesis, possibly due to the activation of T cells. Activation via CD4 or CD8 molecules by OKT4 or OKT8 antibodies did not lead to a T cell-dependent modulation of IgE synthesis. PWM acted in synergy with the enhancing effect of anti-CD3 antibodies for IgE synthesis. In vitro IgG production was less affected. These results indicate that activation of T cell via CD3 molecules may be important in the regulation of IgE immune responses in man. Furthermore, the successful induction of IgE synthesis by anti-CD3 antibody in unfractionated peripheral blood leukocytes culture provides a simple model for investigation of human IgE regulatory mechanism in vitro.