title: Cyclosporine and the immune response: basic aspects.
abstract: Cyclosporine (CsA) is a novel immunosuppressive agent currently used clinically, to prevent rejection of solid organ allografts and to prevent graft-vs.-host disease. Early studies in a variety of animal models exhibited transplantation tolerance after limited treatment with this unique agent. The apparent specific immunological unresponsiveness induced by CsA is thought to be maintained by antigen-specific suppressor T lymphocytes. Studies attempting to dissect the mechanism of action of this unique agent suggested that CsA selectively affected different T lymphocyte populations. Cyclosporine was very effective at inhibiting the production of interleukin-2 (IL-2), a soluble lymphokine known to amplify cytotoxic T cell responses and was also capable of preventing IL-2 receptor expression on the precursor cytotoxic T lymphocyte. In contrast, to the effect on T helper cells and on the precursor cytotoxic T lymphocyte, studies in vitro and in vivo demonstrated that CsA had a sparing effect on suppressor T cell induction. More recent studies have indicated that CsA allows for the amplification of suppressor T lymphocytes independent of interleukin-2 indicating that other cellular and/or soluble factors are important for potentiation of suppressor T lymphocyte activity. However, the molecular action of CsA at the cellular level still remains unresolved. Thus, CsA is not only a useful drug in clinical transplantation but it has become increasingly important as an immunologic probe allowing the dissection of complex cellular interactions involved in the immune response.
mesh_terms: D000818:Animals; D003524:Cyclosporins / Q000494:pharmacology*; D006649:Histocompatibility Antigens / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects*; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology*; D008222:Lymphokines / Q000276:immunology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D008954:Models, Biological; D013347:Subcellular Fractions / Q000276:immunology; D013601:T-Lymphocytes / Q000145:classification; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D003524:Cyclosporins; D006649:Histocompatibility Antigens; D008222:Lymphokines