title: Modification of lymphocyte responsiveness in vitro by lambda carrageenan compared with colloidal silica and depletion of surface adherent cells.
abstract: The effects of the immunosuppressive sulphated polygalactan lambda carrageenan on in vitro models of allograft immunity were compared with the effects of removing macrophages (surface adherent and/or phagocytic cells) by established methods. Carrageenan depressed the primary mixed lymphocyte reactions, but not to the same extent as the removal of macrophages. 2-Mercaptoethanol restored the response. Secondary mixed lymphocyte reactions and responses to phytohaemaglutinin were depressed by carrageenan but not by the removal of macrophages, and in these systems 2-mercaptoethanol failed to restore the responses of carrageenan-treated cultures. In contrast, cell-mediated cytolysis by presensitized lymphocytes was not affected by carrageenan or by colloidal silica. Carrageenan depressed cell-mediated cytolysis only if it was present during the sensitization of the effector cells. We conclude that carrageenan can have two dose-related effects in vitro: one on the macrophage and one on the responding lymphocyte.
mesh_terms: D000818:Animals; D002351:Carrageenan / Q000494:pharmacology*; D003102:Colloids; D003601:Cytotoxicity Tests, Immunologic; D004306:Dose-Response Relationship, Immunologic; D007694:Killer Cells, Natural / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000276:immunology*; D008264:Macrophages / Q000276:immunology*; D008623:Mercaptoethanol / Q000494:pharmacology; D012822:Silicon Dioxide / Q000494:pharmacology*; D013552:Swine
chemical_list: D003102:Colloids; D008623:Mercaptoethanol; D012822:Silicon Dioxide; D002351:Carrageenan