title: Cell interactions in the immune system: the role of self recognition in the targeting of nonspecific effector molecules by helper T cells.
abstract: Helper T cells are activated by cross-linking of their receptors by antigen:Ia complexes on the surface of antigen-presenting cells and B cells. As a result of this cross-linking, the helper T cell releases several lymphokines that in turn affect the Ia-bearing cell with which the helper T cell is in contact. This interaction is cognate when the effect on the target cell is examined, but it operates by a mechanism that is neither antigen specific nor MHC restricted. Whether the cognate nature of this interaction reflects solely the intimate contact of the T cell with the Ia antigen-bearing cell or whether it reflects a receptor-directed focal release of lymphokines remains to be determined. The molecular basis for functional diversity in helper T cells will have to be determined by examining the factors that regulate lymphokine gene expression in such cells, a process that appears to act at several levels.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology*; D002450:Cell Communication; D002460:Cell Line; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D014644:Genetic Variation; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008223:Lymphoma / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2