induction of human in vitro ige synthesis via stimulation by anti‐cd3 antibody

Abstract Mitogens such as pokeweed mitogen, Staphylococcus aureus Cowan I, con‐canavalin 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.