Mitogenic responsiveness of human T-lymphocyte subpopulations: regulation by suppressive Fc-receptor-bearing T cells and influence of fractionation procedures.
The proliferative response induced by leucoagglutinin (La) in different subpopulations of human T lymphocytes was studied. Subpopulations enriched in cells with either high- or low-avidity receptors for sheep erythrocytes (SRBC) (EH +, EL +) were prepared by sequential E-rosetting. In addition, T lymphocytes prepared by E-rosetting under optimal conditions (E + TOT) were fractionated on wheat germ agglutin (WGA)-Sepharose columns, rendering fractions enriched in lymphocytes with either low- or high-avidity receptors for WGA. The T lymphocytes were found to comprise at least three functionally distinct subpopulations, differing with respect to mitogen responsiveness. Cells characterized by high-avidity receptors for WGA and SRBC were highly responsive to La stimulation, regardless of the method used for purification. In contrast, cells with low-avidity receptors for WGA and probably also for SRBC but lacking Fc receptors for IgG responded only marginally but were conditioned to respond when subjected to E-rosetting under optimal conditions. This response was suppressed by lymphocytes with Fc receptors for IgG, which probably also had low-avidity receptors for WGA and SRBC. The lymphocytes with high-avidity receptors for WGA ans SRBC did not appear to be susceptible to suppression by Fc gamma + cells.
D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D007074:Immunoglobulin G; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008934:Mitogens / Q000276:immunology; D010835:Phytohemagglutinins / Q000276:immunology; D011961:Receptors, Fc / Q000276:immunology*; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
D007074:Immunoglobulin G; D008934:Mitogens; D010835:Phytohemagglutinins; D011961:Receptors, Fc; D004247:DNA