The Fc receptor on thymus-derived lymphocytes. IV. Inhibition of binding of antigen-antibody complexes to Fc receptor-positive T cells by anti-Ia sera.

Abstract

Treatment of splenic T [thymus-derived] lymphocytes [mouse] with anti-Ia [immune response-associated] antiserum inhibits the binding of antigen-antibody (AgAb) complexes to the majority (> 50%) of Fc receptor-positive (FcR+) T cells. A similar inhibition was observed with anti-H-2D and anti-H-2K sera but not with anti-Thy 1.2. Despite the presence of Ia determinants on peripheral T cells, as established by the inhibition of AgAb binding, Ia could not be detected on peripheral T cells by immunofluorescence assays. Data obtained with the AgAb-binding inhibition assay indicate that determinants controlled by loci mapping in the I-A and I-C, S or G regions are present on the FcR+ T cells. Subpopulations of T cells within the FcR+ T-cell population may be distinguishable on the basis of which I-region-controlled determinant is expressed. The data are discussed in terms of phenotypic and functional heterogeneity of T lymphocytes.