The immune response to heterologous red cells in mice. V. The effect of cyclophosphamide and cortisone on antigenic competition.

Abstract

The effects of cyclophosphamide and cortisone acetate were examined in a model of antigenic competition between sequentially administered non-cross-reacting red cells from different species. In control mice receiving no drug, the relative immunogenic potency of heterologous red cells given with the first injection failed to determine the degree of unresponsiveness to subsequently injected unrelated cells. However, susceptibility to the suppressive action of previously administered erythrocytes was inversely related to the immunogenicity of the second antigen. Cyclophosphamide given 1 day after the initial red cell injection completely blocked competitive inhibition. On the other hand, impaired reactivity to the second of two sequentially administered antigens was further depressed by cortisone. The results are discussed in terms of targets of drug action and possible sites of antigenic interference.