Characterization of mononuclear phagocytes in schistosomal egg granulomas of athymic mice.
Macrophages from schistosomal egg granulomas of athymic mice (nu/nu GM) and their euthymic littermates (nu/+ GM) were analyzed phenotypically for the expression of antigens encoded by the I-A subregion of the major histocompatibility complex and for their ability to perform as antigen-presenting cells. Only 11 to 15% of nu/nu GM expressed I-A antigens as compared to 61.5 to 75% of nu/+ GM. Although both populations of cells appeared to be equally effective as antigen-presenting cells appropriately sensitized lymphocytes in the presence of specific antigens--soluble schistosomal egg antigen (SEA) and human gamma-globulin (HGG)--only nu/nu GM, but not nu/+ GM, were found to stimulate I-A-restricted proliferation of schistosome-sensitized T cell populations in the absence of SEA added in vitro. Furthermore, nu/nu GM but not nu/+ GM were shown to exhibit significant proliferative capacity in vitro, but this phenomenon could not account for the observed difference in SEA-independent T cell stimulation. Finally, culture supernatants from nu/nu GM displayed significant thymocyte-stimulating activity, consistent with interleukin 1, which was not observed in nu/+ GM. These findings point to significant differences between nu/nu GM and nu/+ GM, which may be part of an adaptive mechanism of granulomatous reactivity in the absence of a competent T cell system.
D000818:Animals; D005260:Female; D006099:Granuloma / Q000276:immunology* / Q000473:pathology; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D007375:Interleukin-1 / Q000502:physiology; D008109:Liver Diseases, Parasitic / Q000276:immunology* / Q000473:pathology; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology* / Q000473:pathology; D051379:Mice; D008808:Mice, Inbred CBA; D008819:Mice, Nude; D010063:Ovum / Q000276:immunology; D012550:Schistosoma mansoni / Q000276:immunology*; D012552:Schistosomiasis / Q000276:immunology* / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology
D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1