title: Relative contributions of NK and CD8 T cells to IFN-gamma mediated innate immune protection against Listeria monocytogenes.
abstract: During the innate immune response to Listeria monocytogenes (LM), the secretion of IFN-gamma is crucial in controlling bacterial numbers. We have shown recently that CD8 T cells have the ability to rapidly secrete IFN-gamma independent of Ag, in response to IL-12 and IL-18, during a LM infection. In the current study, we compared the relative abilities of NK and CD8 T cells to provide innate immune protection. Upon transfer of either NK or memory OT-I T cells (specific for the OVA protein) into IFN-gamma-deficient hosts that were infected subsequently with wild-type LM, both cell types were found in the spleen and had the ability to secrete IFN-gamma. However, the OT-I T cells were more effective at providing innate immune protection as determined by spleen and liver LM burdens. We used immunocytochemistry to demonstrate that upon infection with LM, marginal zone macrophages were localized to the T cell area of the splenic follicle. Transferred memory OT-I T cells were also found in the T cell area of the spleen, co-localizing with the LM and macrophages. In sharp contrast, NK cells were found predominantly in the red pulp region of the spleen. In addition, memory OT-I T cells were also found to be associated with LM lesions in the liver. These results highlight the importance of CD8 T cells in innate immune responses to LM and suggest that their increased protective ability compared with NK cells is the result of their colocalization with LM and macrophages.
authors: Center for Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9093, USA.
authors: Rance E
authors: RE
authors: Berg
authors: Emily
authors: E
authors: Crossley
authors: Sean
authors: S
authors: Murray
authors: James
authors: J
authors: Forman
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology* / Q000637:transplantation; D002460:Cell Line; D002465:Cell Movement / Q000235:genetics / Q000276:immunology; D007113:Immunity, Innate / Q000235:genetics; D007156:Immunologic Memory / Q000235:genetics; D007371:Interferon-gamma / Q000172:deficiency / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology* / Q000637:transplantation; D008089:Listeria monocytogenes / Q000276:immunology; D008088:Listeriosis / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D008099:Liver / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D008264:Macrophages / Q000166:cytology / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000473:pathology
chemical_list: D007371:Interferon-gamma