title: Ia antigen expression and antigen-presenting function by macrophages isolated from hypersensitivity granulomas.
abstract: Macrophages were isolated from granulomas elicited in the liver by the eggs of the trematode Schistosoma mansoni. They were analyzed for the expression of determinants encoded by the I-A subregion of the major histocompatibility complex and for their ability to present antigen in a T cell proliferation assay. Seventy-five to 81% of the macrophages were found to bear I-A antigens after 24 hr in culture; they also were shown to be effective in carrying out antigen-presenting function. Subsequent in vitro cultivation for up to 4 days demonstrated a progressive loss of I-A molecules, which correlated with a corresponding reduction in antigen-presenting capability. The latter was antigen-specific, blocked by monoclonal antibody directed against I-A, and abrogated after depletion of I-A-positive macrophages. Populations of macrophages from hepatic egg granulomas were richer in I-A-positive cells, and were more effective in terms of antigen-presenting capability compared to those obtained from foreign body-type granulomas. These observations suggest a central role for macrophages from infectious granulomas in the induction and maintenance of immunity and hypersensitivity.
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D002469:Cell Separation; D005260:Female; D006099:Granuloma / Q000276:immunology* / Q000469:parasitology; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006968:Hypersensitivity, Delayed / Q000276:immunology*; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D012550:Schistosoma mansoni / Q000276:immunology; D012552:Schistosomiasis / Q000276:immunology / Q000469:parasitology; D005719:gamma-Globulins / Q000276:immunology
chemical_list: D000949:Histocompatibility Antigens Class II; D005719:gamma-Globulins