T3-T cell receptor (Ti) complex-independent activation of T cells by wheat germ agglutinin.
The T3-Ti complex appears to play a central role in the activation of T cells by antigens and mitogens. Wheat germ agglutinin (WGA) is a unique lectin which inhibits T cell proliferation induced by mitogens, but it also induces marked IL 2 production by peripheral blood T cells. The pattern of responses induced by WGA suggests that this lectin may use a different mechanism of T cell activation other than the mechanism employed by the common T cell stimulants. We first investigated the production of IL 2 by Jurkat cells (E6-1) stimulated with WGA, before and after modulation of the surface T3-Ti complex. IL 2 production was markedly reduced after modulation of the T3 antigen from the cell surface when these cells were stimulated with PHA. In contrast, little change was observed in WGA-induced IL 2 production after modulation. Furthermore, we examined the effect of WGA on a T3-mutant of E6-1 cells (T3.1) which does not produce IL 2 in response to PHA or PHA plus PMA. WGA-stimulated T3.1 cells produced a significant amount of IL 2 with or without added PMA. In addition, a small but consistent rise in intracytoplasmic free calcium was observed when these cells were stimulated with WGA. These results demonstrate the presence of an alternative mechanism of T cell activation independent of the T3-Ti complex.
D000117:Acetylglucosamine / Q000494:pharmacology; D000954:Antigens, Surface / Q000276:immunology; D017252:CD3 Complex; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002460:Cell Line; D006801:Humans; D007152:Immunologic Capping; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D009154:Mutation; D010835:Phytohemagglutinins / Q000494:pharmacology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D014909:Wheat Germ Agglutinins / Q000276:immunology*
D000954:Antigens, Surface; D017252:CD3 Complex; D007376:Interleukin-2; D010835:Phytohemagglutinins; D011948:Receptors, Antigen, T-Cell; D014909:Wheat Germ Agglutinins; D000001:Calcimycin; D002118:Calcium; D000117:Acetylglucosamine