title: In vitro T cell-mediated killing of Pseudomonas aeruginosa. I. Evidence that a lymphokine mediates killing.
abstract: Previous studies have demonstrated in vivo that T cells can provide protective immunity, in the absence of antibody, against infection with the extracellular Gram-negative bacterium Immunotype 1 (IT-1) Pseudomonas aeruginosa. We established an in vitro system in which immune T cells, after reexposure to bacterial antigens and to macrophages, secrete a product that kills the bacteria. Although macrophages are required for in vitro killing, they function neither as antigen-presenting nor as phagocytic cells in this system. T cells from animals immunized against a different P. aeruginosa immunotype will not kill IT-1 organisms; but the supernatants produced by IT-1 immune T cells after exposure to macrophages and IT-1 P. aeruginosa organisms are nonspecifically effective in killing unrelated bacteria. Because the supernatants from immune T cells lose their bactericidal properties upon minimal dilution, we conclude that if this mechanism is active in vivo, it must play a role in local immunity.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004306:Dose-Response Relationship, Immunologic; D007111:Immunity, Cellular; D008222:Lymphokines / Q000494:pharmacology*; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D011135:Polysaccharides, Bacterial / Q000008:administration & dosage; D011550:Pseudomonas aeruginosa / Q000276:immunology* / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D014747:Vinblastine / Q000494:pharmacology
chemical_list: D008222:Lymphokines; D011135:Polysaccharides, Bacterial; D014747:Vinblastine