title: Nippostrongylus brasiliensis-induced depression of heterologous immune responses: effects of the histamine H2 receptor antagonist, cimetidine.
abstract: Both mucosal and systemic immune responses are depressed in mice infected with the nematode Nippostrongylus brasiliensis and this is correlated with a striking increase in the numbers of histamine-containing, mucosal-associated mast cells. As suppressor T cells bear histamine H2 receptors, we have used the H2 antagonist, cimetidine, to test whether histamine mediates N. brasiliensis-induced immunodepression. In uninfected mice, mitogenic responses to PHA and Con A were increased by treatment with cimetidine; in some experiments this treatment also increased antibody responses to a T-dependent antigen (TNP-BGG). By contrast, these T- and B-cell responses were markedly depressed in mice infected with N. brasiliensis, and cimetidine treatment did not alter this parasite-induced immunodepression. These results imply that although histamine can modulate immune responses in uninfected animals, it is not a major component of the immunoregulatory pathway induced by infection with N. brasiliensis.
mesh_terms: D000818:Animals; D000909:Antibodies, Helminth / Q000096:biosynthesis*; D000941:Antigens / Q000276:immunology; D002927:Cimetidine / Q000494:pharmacology*; D005260:Female; D007108:Immune Tolerance; D007070:Immunoglobulin A / Q000096:biosynthesis; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008808:Mice, Inbred CBA; D008934:Mitogens / Q000494:pharmacology; D009349:Nematode Infections / Q000276:immunology*; D009559:Nippostrongylus / Q000187:drug effects / Q000276:immunology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology
chemical_list: D000909:Antibodies, Helminth; D000941:Antigens; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008934:Mitogens; D002927:Cimetidine