title: T cell expansion is regulated by activated Gr-1+ splenocytes.
abstract: CD4+ T cell proliferation depends on the balance between NO and extra-cellular superoxide (O2-). By reducing NO bio-availability, O2- promotes splenic T cell proliferation and immune response intensity. Here, we show that spleen cells from naïve mice produced neither NO nor O2- during T cell activation, but Gr-1+ splenocytes from primed mice regulated Ag-specific T cell expansion via production of both molecules. Purified splenic Gr-1+ cells included mostly granulocytes at various stages of maturation, as well as monocytes. Activation or recruitment of regulatory Gr-1+ cells was dependent on immunization with CFA. Importantly, these regulatory cells were not detected in draining lymph nodes. These data suggest that innate Gr-1+ splenic cells regulate adaptive immunity.
authors.affiliation: Department of Neurology, University of Southern California Keck School of Medicine, Los Angeles, CA, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: Dietlin
authors.forename: F M
authors.initials: FM
authors.lastname: Hofman
authors.forename: W
authors.initials: W
authors.lastname: Gilmore
authors.forename: S A
authors.initials: SA
authors.lastname: Stohlman
authors.forename: R C
authors.initials: RC
authors.lastname: van der Veen
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D005620:Freund's Adjuvant; D007155:Immunologic Factors / Q000096:biosynthesis / Q000502:physiology; D008055:Lipids; D008213:Lymphocyte Activation / Q000276:immunology; D008285:Major Histocompatibility Complex / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009169:Mycobacterium tuberculosis / Q000276:immunology; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology; D019707:Receptors, Chemokine / Q000096:biosynthesis*; D016192:Resting Phase, Cell Cycle / Q000276:immunology; D013154:Spleen / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism
chemical_list: C503133:Gr-1 protein, mouse; D007155:Immunologic Factors; D008055:Lipids; D019707:Receptors, Chemokine; C114843:incomplete Freund's adjuvant; D013481:Superoxides; D009569:Nitric Oxide; D005620:Freund's Adjuvant