title: Demonstration of a soluble mediator that induces exudates rich in Ia-positive macrophages.
abstract: Previous studies have shown that Listeria monocytogenes-immune T cells, adoptively transferred into normal mice with killed Listeria organisms, induced peritoneal exudates rich in Ia-positive macrophages. We show now that culture fluids generated by Listeria-immune exudate cells and Listeria contain an activity that elicits Ia-rich exudates when injected intraperitoneally. The factor that recruits Ia-positive macrophages must be injected several times during a 2-d period for optimal demonstration of its activity. The induction of the factor is immunologically specific and requires Ia-positive macrophages, primed T lymphocytes, and antigen challenge. The factor is a nondialyzable protein and is not genetically restricted in its activity. The macrophages in the exudates induced by the factor bear Fc receptors, take up latex, synthesize I-A, but bear few C3 receptors. We have thus identified an immune mediator capable of controlling the Ia phenotype of the exudate macrophages.
mesh_terms: D000818:Animals; D000941:Antigens; D005122:Exudates and Transudates / Q000276:immunology; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D007111:Immunity, Cellular; D008087:Listeria / Q000276:immunology; D008222:Lymphokines / Q000502:physiology; D008264:Macrophages / Q000276:immunology*; D008297:Male; D051379:Mice; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000941:Antigens; D000949:Histocompatibility Antigens Class II; D008222:Lymphokines