title: Downmodulation of the inflammatory response to bacterial infection by gammadelta T cells cytotoxic for activated macrophages.
abstract: Although gammadelta T cells are involved in the regulation of inflammation after infection, their precise function is not known. Intraperitoneal infection of T cell receptor (TCR)-delta(-/-) mice with the intracellular bacterium Listeria monocytogenes resulted in the development of necrotic foci in the livers. In contrast, the peritoneal cavities of infected TCR-delta(-/-) mice contained an accumulation of low density activated macrophages and a reduced percentage of macrophages undergoing apoptosis. gammadelta T cell hybridomas derived from mice infected with Listeria were preferentially stimulated by low density macrophages from peritoneal exudates of infected mice. Furthermore, primary splenic gammadelta T cells isolated from Listeria-infected mice were cytotoxic for low density macrophages in vitro, and cytotoxicity was inhibited in the presence of antibodies to the gammadelta TCR. These results demonstrate a novel interaction between gammadelta T cells and activated macrophages in which gammadelta T cells are stimulated by terminally differentiated macrophages to acquire cytotoxic activity and which, in turn, induce macrophage cell death. This interaction suggests that gammadelta T cells regulate the inflammatory response to infection with intracellular pathogens by eliminating activated macrophages at the termination of the response.
authors.affiliation: Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Egan
authors.forename: S R
authors.initials: SR
authors.lastname: Carding
mesh_terms: D000818:Animals; D002469:Cell Separation / Q000379:methods; D006825:Hybridomas; D008088:Listeriosis / Q000276:immunology*; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D010537:Peritoneum / Q000276:immunology; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D016692:Receptors, Antigen, T-Cell, gamma-delta