title: The effects of cyclosporin and hydrocortisone on human T-lymphocyte colony formation.
abstract: The immunosuppressive activities of two compounds, cyclosporin A and hydrocortisone, were evaluated using a human T lymphocyte colony assay. Both compounds produced a dose-related reduction in colony formation. With cyclosporin, concentrations of 1.0-100 micrograms/ml virtually abolished PHA-induced lymphocyte growth; as little as 0.01 microgram/ml decreased clonal growth by 48%. Suppression was observed as late as 4 days after the addition of PHA. The addition of exogenous IL-2 did not completely restore clonal growth to normal. Similarly, hydrocortisone, in concentrations of 0.4 microgram/ml, produced a 96% inhibition in clonal growth. Partial suppression could also be obtained if the drug was added as late as 4 days after PHA. Exogenous IL-2 completely reversed the inhibitory effects of hydrocortisone. By contrast, IL-1 was able to only partially restore growth potential. Parallel studies using TPA indicated that both immunosuppressants inhibited responses to this mitogen. However, in plates containing both TPA and PHA, hydrocortisone failed to impair clonal growth.
mesh_terms: D003524:Cyclosporins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology*; D007165:Immunosuppression Therapy; D007700:Kinetics; D008213:Lymphocyte Activation / Q000187:drug effects; D010835:Phytohemagglutinins; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D003524:Cyclosporins; D010835:Phytohemagglutinins; D013755:Tetradecanoylphorbol Acetate; D006854:Hydrocortisone