Induction of an auto-anti-IgE response in rats I. Effects on serum IgE concentrations.

With a view to specifically suppressing the IgE isotype, rats of high (BN) and low (PVG.RT1u) IgE-responding phenotypes were immunized with a highly purified rat IgE myeloma (IR2) in an attempt to induce an anto-anti-IgE response. Rat IgE antibodies against epsilon determinants were detected in the serum of IR2-immunized animals using a solid-phase (plate) radioimmunoassay. The auto-anti-IgE antibodies detected were found to bind to IR2, to a second rat IgE myeloma (IR162) and to mouse monoclonal IgE but not rat IgG. The specificity of the anti-epsilon binding was shown by inhibition studies. The raising of an auto-anti-IgE response in PVG.RT1u rats severely depleted the serum level of circulating IgE for at least 8 weeks. In BN rats, immunization with IR2 caused marked fluctuations in serum IgE levels. The rats in both strains remained healthy throughout the experiment. The rate and route of IgE break down was not altered in anti-IgE-producing rats. The relevance of the present model in understanding and possibly controlling allergic disorders is considered.