title: Inhibition of macrophage phagocytosis in cryptococcosis: phenotypic analysis of the suppressor cell.
abstract: Our laboratory has previously reported a suppressor cell mechanism to occur late in the course of a lethal infection with Cryptococcus neoformans. A soluble factor was found to be responsible for inhibition of the phagocytic activity of a subpopulation of peritoneal macrophages. The suppressor cell was identified as a T cell which required in vitro stimulation with specific antigen before the phagocytosis-inhibiting lymphokine (PIL) was produced. PIL action was allospecific and occurred in animals given tolerogenic doses of cryptococcal and noncryptococcal antigens. The current investigation has further characterized the T lymphocyte responsible for PIL activity. The suppressor cell was found to be in a cyclophosphamide-sensitive pathway. PIL activity was not detected when spleen cell populations were treated with anti-I-J and complement or anti-Lyt-2 and complement. Likewise, a mixture of anti-I-J-treated and anti-Lyt-2-treated cells was incapable of synthesizing the lymphokine. Treatment of spleen cells with anti-Lyt-1.2 or anti-L3T4 and complement did not eliminate PIL synthesis. Further analysis of the genetic restrictions associated with the PIL-macrophage interaction revealed regulation by the I-J subregion of the major histocompatibility complex.
authors.affiliation: Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City 73190.
authors.forename: R
authors.initials: R
authors.lastname: Blackstock
authors.forename: N C
authors.initials: NC
authors.lastname: Hernandez
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D003453:Cryptococcosis / Q000276:immunology*; D003520:Cyclophosphamide / Q000494:pharmacology; D004731:Endotoxins / Q000494:pharmacology; D006239:Haplotypes; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D008264:Macrophages / Q000502:physiology*; D008285:Major Histocompatibility Complex; D051379:Mice; D010587:Phagocytosis; D013491:Suppressor Factors, Immunologic / Q000502:physiology*; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D004731:Endotoxins; D000949:Histocompatibility Antigens Class II; D013491:Suppressor Factors, Immunologic; D003520:Cyclophosphamide