Human suppressor T cells: induction, differentiation, and regulatory functions.
T-cell-mediated suppression of human immune responses involves a complex interaction between distinct lymphocyte subsets with suppressor-inducer and suppressor-effector functions. Recent studies with subset-specific monoclonal antibodies have defined a characteristic phenotype of suppressor-inducer cells (CD4+ Leu8+ 2H4+ 4B4-) that can be distinguished from that of helper cells for antibody synthesis (CD4+ Leu8- 2H4- 4B4+). Similarly, suppressor-effector cells (CD8+CD11+Tp44-) can typically be defined as a subset separable from cytotoxic T cells (CD8+CD11-Tp44+). Both antigen-specific and nonspecific interactions are important in suppressor T-cell activation and function. Soluble signals required for differentiation of CD8+ suppressor cells include an indomethacin-sensitive monocyte product and interferon gamma. In contrast, proliferation of the CD8+ suppressor cell subset depends on stimulation first by a product of CD4+Leu8+ cells, T suppressor cell growth factor, and second by interleukin 2. Although the molecular basis of antigen-specific interactions between CD4+ and CD8+ cells in suppressor cell generation has not been defined, it may involve both conventional, presumably MHC-restricted, interactions between antigen and antigen receptors, as well as anti-idiotypic interactions of suppressor-effectors with determinants on suppressor-inducer receptors. Progress in elucidating requirements for activation, growth, and differentiation of suppressor cells should facilitate long-term culture of such cells and lead to clearer understanding of mechanisms of suppressor-cell mediated immunoregulation.
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D002454:Cell Differentiation; D006801:Humans; D007376:Interleukin-2 / Q000502:physiology; D008211:Lymphocyte Cooperation; D011043:Pokeweed Mitogens / Q000494:pharmacology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000145:classification / Q000166:cytology / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D007376:Interleukin-2; D011043:Pokeweed Mitogens