title: MHC class-I-restricted CD8 T cells play a protective role during primary Salmonella infection.
abstract: Protective immunity against Salmonella infection is known to require CD4 Th1 cells and B cells, but the role of MHC class-I-restricted CD8 T cells is less clear. Previous studies have suggested that CD8 T cells participate in secondary, but not primary, bacterial clearance. However, these studies have used experimental models that are difficult to interpret and do not clearly isolate the role of MHC class-I-restricted CD8 T cells from other cell populations. Here, we examined the role of class-I-restricted T cells in protection against Salmonella infection using mice lacking all classical MHC class-Ia molecules, perforin, or granzyme B. Immunized K(b)D(b)-, perforin-, granzyme B-, or perforin/granzyme B-deficient mice were able to resolve secondary infection with virulent Salmonella, demonstrating that class-I-restricted CTLs are not required for acquired immunity. However, during primary infection with attenuated bacteria, bacterial clearance was delayed in each of these mouse strains when compared to wild-type mice. Taken together, these data demonstrate that CD8 T cells are not required for acquired immunity to Salmonella, but can play a protective role in resolving primary infection with attenuated bacteria.
authors.affiliation: Center for Comparative Medicine, Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA. joolee@ucdavis.edu
authors.forename: Seung-Joo
authors.initials: SJ
authors.lastname: Lee
authors.forename: Samantha
authors.initials: S
authors.lastname: Dunmire
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: McSorley
mesh_terms: D000818:Animals; D058491:Bacterial Load; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003602:Cytotoxicity, Immunologic / Q000276:immunology; D053804:Granzymes / Q000172:deficiency / Q000235:genetics; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D054353:Perforin / Q000172:deficiency / Q000235:genetics; D012481:Salmonella Infections, Animal / Q000276:immunology*; D012485:Salmonella typhi / Q000276:immunology* / Q000472:pathogenicity
chemical_list: D015395:Histocompatibility Antigens Class I; D054353:Perforin; D053804:Granzymes