Effect of wheat germ agglutinin on the interleukin pathway of human T lymphocyte activation.
Wheat germ agglutinin (WGA) inhibits proliferation of human peripheral blood mononuclear cells (PBMC) induced by mitogens and antigens. We investigated the mechanism by which WGA inhibits PHA-induced human lymphocyte proliferation with regard to the interleukin pathway. Our data revealed that although PBMC-proliferation was markedly suppressed by WGA, levels of IL 2 activity in WGA-inhibited cultures were not reduced, but instead were increased, suggesting failure to utilize IL 2. Furthermore, the addition of exogenous IL 2 failed to overcome the suppression. Consistent with these observations, culturing PBMC with PHA plus WGA markedly decreased the number of high-affinity IL 2 receptor per cell, as determined by binding of purified [3H]IL 2, relative to cultures containing PHA alone. WGA immobilized on support beads bound detergent-solubilized IL 2 receptors from PHA-activated T cells, but did not bind human IL 2. However, WGA did not competitively block the binding of [3H]IL 2 to PHA-induced lymphoblasts. These results suggest that WGA inhibits lymphocyte proliferation by binding to and decreasing the number of high-affinity IL 2 receptors displayed on T cells, without impairing IL 2 production.
D002478:Cells, Cultured; D004261:DNA Replication / Q000187:drug effects; D006801:Humans; D007376:Interleukin-2 / Q000276:immunology*; D007700:Kinetics; D037102:Lectins / Q000494:pharmacology; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins / Q000494:pharmacology; D011971:Receptors, Immunologic / Q000032:analysis; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000276:immunology*; D014909:Wheat Germ Agglutinins
D007376:Interleukin-2; D037102:Lectins; D010835:Phytohemagglutinins; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D014909:Wheat Germ Agglutinins