title: 8-Methoxypsoralen inhibits lymphocyte proliferation in vitro in the absence of ultraviolet radiation.
abstract: 8-Methoxypsoralen was assessed for its effects on in vitro lymphocyte proliferation in the absence of ultraviolet radiation. 8-Methoxypsoralen inhibited both the phytohemagglutinin and concanavalin A-induced proliferation of normal human peripheral blood lymphocytes in a time and dose-dependent manner. This inhibition did not require the photoactivation of 8-methoxypsoralen in these cells. Suppressed lymphocyte proliferation in the presence of 8-methoxypsoralen could not be overcome by addition of exogenous interleukin-2. The observed decrease in lymphocyte proliferation hyporesponsiveness to interleukin-2 correlated with the ability of 8-methoxypsoralen to induce a dose-dependent decrease in interleukin-2 receptor expression on phytohemagglutinin-stimulated lymphocytes. Since interleukin-2 receptors play a central role in lymphocyte proliferation and immune reactivity, their decrease may explain the mechanism by which 8-methoxypsoralen impairs lymphocyte function.
mesh_terms: D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D006801:Humans; D007165:Immunosuppression Therapy; D066298:In Vitro Techniques; D008213:Lymphocyte Activation / Q000187:drug effects*; D008222:Lymphokines / Q000494:pharmacology; D008730:Methoxsalen / Q000494:pharmacology*; D011971:Receptors, Immunologic / Q000378:metabolism; D015375:Receptors, Interleukin-2; D014466:Ultraviolet Rays
chemical_list: D008222:Lymphokines; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D008730:Methoxsalen