title: CD4+CD25+ regulatory T cells control innate immune reactivity after injury.
abstract: Major injury initiates a systemic inflammatory response that can be detrimental to the host. We have recently reported that burn injury primes innate immune cells for a progressive increase in TLR4 and TLR2 agonist-induced proinflammatory cytokine production and that this inflammatory phenotype is exaggerated in adaptive immune system-deficient (Rag1(-/-)) mice. The present study uses a series of adoptive transfer experiments to determine which adaptive immune cell type(s) has the capacity to control innate inflammatory responses after injury. We first compared the relative changes in TLR4- and TLR2-induced TNF-alpha, IL-1beta, and IL-6 production by spleen cell populations prepared from wild-type (WT), Rag1(-/-), CD4(-/-), or CD8(-/-) mice 7 days after sham or burn injury. Our findings indicated that splenocytes prepared from burn-injured CD8(-/-) mice displayed TLR-induced cytokine production levels similar to those in WT mice. In contrast, spleen cells from burn-injured CD4(-/-) mice produced cytokines at significantly higher levels, equivalent to those in Rag1(-/-) mice. Moreover, reconstitution of Rag1(-/-) or CD4(-/-) mice with WT CD4(+) T cells reduced postinjury cytokine production to WT levels. Additional separation of CD4(+) T cells into CD4(+)CD25(+) and CD4(+)CD25(-) subpopulations before their adoptive transfer into Rag1(-/-) mice showed that CD4(+)CD25(+) T cells were capable of reducing TLR-stimulated cytokine production levels to WT levels, whereas CD4(+)CD25(-) T cells had no regulatory effect. These findings suggest a previously unsuspected role for CD4(+)CD25(+) T regulatory cells in controlling host inflammatory responses after injury.
authors.affiliation: Department of Surgery (Immunology), Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Murphy
authors.forename: Niamh
authors.initials: N
authors.lastname: Ni Choileain
authors.forename: Yan
authors.initials: Y
authors.lastname: Zang
authors.forename: John A
authors.initials: JA
authors.lastname: Mannick
authors.forename: James A
authors.initials: JA
authors.lastname: Lederer
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D002056:Burns / Q000235:genetics / Q000276:immunology* / Q000382:microbiology / Q000473:pathology*; D015704:CD4 Antigens / Q000235:genetics; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics; D018836:Inflammation Mediators / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000502:physiology; D007375:Interleukin-1 / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010457:Peptidoglycan / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis*; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism* / Q000637:transplantation; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D015704:CD4 Antigens; D018398:Homeodomain Proteins; D018836:Inflammation Mediators; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D010457:Peptidoglycan; D011956:Receptors, Cell Surface; D015375:Receptors, Interleukin-2; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; C064658:RAG-1 protein