Generation of cell-derived factors in vitro which modulate IgE synthesis.

Generation of IgE-specific suppressor factors in vitro upon stimulation of murine lymphocytes with IgE was studied. High-molecular weight factors (greater than 50 kilodalton) suppressed in vivo IgE response as well as de novo IgE synthesis in vitro. Further, suppression of IgE synthesis in vitro by fractions of low molecular weight supernatants absorbed with IgE-Sepharose was obtained, suggesting a potent role for IgE binding factors in IgE synthesis.