Regulation of rat IgE responses by immune complexes.

The immunizing ability of immune complexes preformed between EA and EA-hyperimmune serum was investigated in adult rats. After immunization with complexes at equivalence, the pattern of suppressed IgE responsiveness was similar to that induced when a small volume of immune serum accompanied routine immunization. We have suggested that the underlying principle is the same, and that the IgE response can be regulated by immune complexes. The ability to influence an ongoing IgE response was determined by treating with complexes at various times after immunization. While the primary IgE levels were differentially affected, the most consistent suppression was seen at the secondary stage. The data suggest that a stage of B-cell differentiation has been interrupted and that IgE antibody-producing cells have been prevented from developing.