title: Histamine suppression of lymphocyte activation.
abstract: Histamine suppresses lymphocyte transformation induced by the mitogen Con A. The effect is dose-related and is not blocked by H1 or H2 antagonists. High dose of H2 antagonists (10(-3) M) enhances the suppression induced by histamine. The proliferation of T cells alone cultured with histamine is suppressed indicating that histamine can exert its effect directly on T cell proliferation without the requirement for accessory cells. Atopic subjects are more sensitive to histamine-induced suppression than normals. The presence of histamine produced locally during a Type I response may provide a mechanism for preventing the proliferation of sensitized T cells which enter the site of antigen stimulation. In the atopic, who already has the immunological machinery to mount cell-mediated immune responses to pollens, this increased histamine sensitivity may be protective in suppressing unwanted delayed hypersensitivity reactions.
mesh_terms: D000328:Adult; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D006633:Histamine Antagonists / Q000494:pharmacology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology
chemical_list: D006633:Histamine Antagonists; D003208:Concanavalin A; D006632:Histamine