title: Potentiation of mitogen-induced human T-lymphocyte activation by retinoic acid.
abstract: The capacity of retinoic acid to modulate human T-lymphocyte and B-lymphocyte activation by mitogens was examined. T-lymphocyte proliferation stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA) or phytohemagglutinin was enhanced by 5 nM to 5 microM retinoic acid in a dose-dependent manner with a 65 +/- 35% (SD) increase (n = 6, P less than 0.01) in TPA-stimulated proliferation induced by 5 microM retinoic acid. Retinoic acid enhanced T-lymphocyte proliferation over a wide range of background proliferation induced by different TPA concentrations. Retinoic acid alone did not stimulate T-lymphocyte proliferation. In contrast retinoic acid inhibited B-lymphocyte proliferation stimulated by TPA or phytohemagglutinin with 26.7 +/- 23.4% inhibition of TPA-stimulated proliferation induced by 5 microM retinoic acid (P less than 0.02). Retinoic acid had intermediate effects on the proliferation of different mixtures of T- and B-lymphocytes stimulated by TPA or phytohemagglutinin. The recognition that retinoic acid has opposing effects on human T- and B-lymphocyte activation by mitogens may account for the conflicting reports of the effects of retinoids on the immune response of unpurified human lymphocyte preparations.
mesh_terms: D004305:Dose-Response Relationship, Drug; D006801:Humans; D066298:In Vitro Techniques; D008213:Lymphocyte Activation / Q000187:drug effects*; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D010835:Phytohemagglutinins; D014212:Tretinoin; D013755:Tetradecanoylphorbol Acetate; D013936:Thymidine