title: Dual role of CCR2 during initiation and progression of collagen-induced arthritis: evidence for regulatory activity of CCR2+ T cells.
abstract: Chemokines play an important role in the recruitment of leukocytes and have recently been shown to also attract regulatory T cells. Using blocking mAbs, we analyzed the role of the chemokine receptor CCR2 during initiation and progression of collagen-induced arthritis in mice. Blockade of CCR2 from days 0 to 15 markedly improved clinical signs of arthritis and histological scores measuring leukocyte infiltration, synovial hyperplasia, and bone and cartilage erosion. CCR2 blockade during disease initiation significantly reduced plasma titers of collagen Abs in vivo. In vitro CCR2 blockade also interfered with collagen-specific activation and proliferation of T cells. Surprisingly, CCR2 blockade from days 21 to 36 markedly aggravated clinical and histological signs of arthritis and increased the humoral immune response against collagen. We show that CCR2 is expressed on regulatory T cells. Purified CCR2+ T cells are fully anergic toward polyclonal and collagen-specific activation and potently suppress activation of other T and B cells. The subpopulation of CCR2+ CD25+ regulatory T cells increases approximately 5-fold in the progression phase, while CCR2 expression on other leukocyte populations remains unchanged. These findings identify CCR2+ T cells as regulatory T cells and indicate that CCR2 also plays an important role in down-modulating an inflammatory response.
authors.affiliation: Medical Policlinic, University of Munich, Pettenkoferstrasse 8a, 80336 Munich, Germany.
authors.forename: Hilke
authors.initials: H
authors.lastname: Brühl
authors.forename: Josef
authors.initials: J
authors.lastname: Cihak
authors.forename: Martin A
authors.initials: MA
authors.lastname: Schneider
authors.forename: Jirí
authors.initials: J
authors.lastname: Plachý
authors.forename: Tamara
authors.initials: T
authors.lastname: Rupp
authors.forename: Isabell
authors.initials: I
authors.lastname: Wenzel
authors.forename: Mehdi
authors.initials: M
authors.lastname: Shakarami
authors.forename: Stefan
authors.initials: S
authors.lastname: Milz
authors.forename: Joachim W
authors.initials: JW
authors.lastname: Ellwart
authors.forename: Manfred
authors.initials: M
authors.lastname: Stangassinger
authors.forename: Detlef
authors.initials: D
authors.lastname: Schlöndorff
authors.forename: Matthias
authors.initials: M
authors.lastname: Mack
mesh_terms: D000818:Animals; D019138:Antibodies, Blocking / Q000008:administration & dosage; D001169:Arthritis, Experimental / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D016466:CHO Cells; D002417:Cattle; D002478:Cells, Cultured; D019742:Chemokines, CC / Q000378:metabolism*; D017635:Clonal Anergy / Q000276:immunology; D024043:Collagen Type II / Q000008:administration & dosage / Q000276:immunology*; D006224:Cricetinae; D018450:Disease Progression; D007117:Immunization, Secondary; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D054390:Receptors, CCR2; D019707:Receptors, Chemokine / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D019138:Antibodies, Blocking; C515335:Ccr2 protein, mouse; D019742:Chemokines, CC; D024043:Collagen Type II; D054390:Receptors, CCR2; D019707:Receptors, Chemokine