| Abstract: | An in vitro experimental system for the induction of human IgE production has been established with human peripheral blood lymphocytes (PBL). For the assessment of IgE produced in vitro, a sensitive ELISA method has been developed by employing monoclonal anti-IgE antibodies. The stimulation of PBL with pokeweed mitogen plus Staphylococcus aureus strain Cowan I induced polyclonal IgE response. T cells from patients with pulmonary tuberculosis, after activation with purified protein derivative and/or IgE, suppressed selectively IgE response, and the suppressive activity was found to be mediated by IgE-specific suppressor factor with affinity for IgE molecules. The suppressive activity was effective both on spontaneous IgE production as well as on mitogen- or antigen-induced IgE response in the PBL culture from atopic patients. The affinity of the suppressor factor for IgE was suggested to be due to the structural similarity with Fc epsilon R on B cells. Absorption experiment suggest that the factor may bear class II major histocompatibility complex (MHC) molecules, although its effect was not MHC-restricted. |
