title: Evidence for the opposing roles of different gamma delta T cell subsets in macrophage homeostasis.
abstract: To ensure invading pathogens are eliminated with minimal damage to host tissues it is essential that macrophage activation be tightly regulated. Previously we demonstrated that a subset of gammadelta T cells (Vgamma1(+)) contributes to resolving pathogen-induced immune responses by killing activated macrophages. However, the exaggerated macrophage response seen in infected Vgamma1(+) T cell-deficient mice suggests that gammadelta T cells play a broader role in macrophage homeostasis and other subsets might promote macrophage activation. Using a macrophage:gammadelta T cell co-culture system we have shown that gammadelta T cells increase the activity of macrophages activated in vivo by Listeria monocytogenes infection. In a dose-dependent manner, gammadelta T cells up-regulated production of cytokines (TNF-alpha, IL-6, IL-10) and chemokines (MIP-1alpha, MIP-1beta) by Listeria-elicited macrophages. The ability to increase macrophage cytokine production was prominent among Vgamma4(+) gammadelta T cells. Reciprocally, Vgamma4(+) gammadelta T cells were activated by Listeria-elicited macrophages, resulting in production of the anti-inflammatory cytokine, IL-10. gammadelta T cell adoptive transfer experiments showed that Vgamma4(+) T cells protected TCRdelta(-/-) mice against Listeria-induced liver injury and necrosis. These findings identify distinct and non-overlapping roles for gammadelta T cell subsets in regulating macrophage function during pathogen-induced immune responses.
authors.affiliation: Research Institute of Molecular and Cellular Biology, The University of Leeds, Leeds, UK.
authors.forename: Daniela
authors.initials: D
authors.lastname: Tramonti
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Andrew
authors.forename: Kate
authors.initials: K
authors.lastname: Rhodes
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Newton
authors.forename: Simon R
authors.initials: SR
authors.lastname: Carding
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D018925:Chemokines / Q000378:metabolism; D018920:Coculture Techniques; D004306:Dose-Response Relationship, Immunologic; D006706:Homeostasis / Q000276:immunology*; D008089:Listeria monocytogenes / Q000276:immunology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism*; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism* / Q000382:microbiology
chemical_list: D018925:Chemokines; D016692:Receptors, Antigen, T-Cell, gamma-delta