Antibody responses of the IgE class are, like other immunoglobulin classes, regulated by a finely-tuned network of complex cellular and molecular interactions (1). Previous studies conducted in our laboratory (2, 3) have provided new insights into the differences in control mechanisms that result in individuals manifesting either the high (allergic) or low (nonallergic) IgE responder phenotype. These experiments have shown that certain manipulations (i.e. low dose X-irradiation) convert normally low responder mice to high IgE responders, apparently by diminishing a suppressor T-cell mechanism which normally dampens, rather selectively, IgE antibody production in such individuals. Similar findings have been made by Watanabe et al. (4).
Recently, we have been studying the types of manipulations that could reverse the high IgE responsive state back to a low one. These studies (2, 3, 5, 6) have demonstrated that the high IgE responses induced in low responder mice can be substantially diminished, and even abolished, by passively transfusing serum or ascetic fluid from donor mice previously inoculated with mycobacterial-containing complete Freund's adjuvant (CFA). Because the suppressive activity of CFA-immune serum or ascitic fluid is so highly selective for IgE antibody production, we have recently termed these serum substances suppressive factors of allergy (SFA) (2, 3).
The present study was undertaken to determine whether alternative means, particularly those that avoid administration of CFA, could be devised for the induction of SFA. Herein, we report the effectiveness of allogeneic lymphoid cell interactions in inducing SFA, both in vivo and in vitro, as well as the potent suppressive effects of an in vivo allogeneic effect on irradiation enhanced IgE antibody production in low responder mice.