title: Important role of interleukin-3 in the early phase of collagen-induced arthritis.
abstract: OBJECTIVE
  Activation of basophils contributes to memory immune responses and results in exacerbation of collagen-induced arthritis (CIA). We undertook the present study to analyze the production and biologic effects of interleukin-3 (IL-3), a strong activator of basophils, in CIA.
  
  
  METHODS
  Arthritis was induced by immunization with type II collagen. Mice were treated with blocking monoclonal antibodies against IL-3 or with recombinant IL-3. Clinical scoring, histologic analysis, fluorescence-activated cell sorter analysis, enzyme-linked immunosorbent assay, and cell culturing were performed to assess disease activity and IL-3 production.
  
  
  RESULTS
  IL-3 was produced in large quantities by collagen-specific CD4+ T cells in the spleen and was present in the synovial tissue during onset of arthritis, but was down-regulated in paws with severe inflammation. Blockade of IL-3 during the time of arthritis onset resulted in profound improvement of the disease, with reductions in synovial leukocyte and cytokine levels, peripheral blood basophil levels, and anticollagen antibody titers. Blockade of IL-3 during the late phase of arthritis had no beneficial effect. Administration of recombinant IL-3 during onset of arthritis induced a marked exacerbation of the disease, with increased peripheral blood basophil and plasma IL-6 levels and increased titers of anticollagen antibody. In studies of the regulation of IL-3 expression in CD4+ T cells, IL-6 and IL-4 suppressed the release of IL-3 by activated CD4+ T cells, whereas lipopolysaccharide and CpG DNA up-regulated IL-3 secretion in activated CD4+ T cells by acting on costimulatory cells.
  
  
  CONCLUSIONS
  Taken together, the present results demonstrate for the first time that IL-3 has an important role in the early phase of CIA.
authors.affiliation: University Hospital Regensburg, Department of Internal Medicine II, Regensburg, Germany.
authors.forename: Hilke
authors.initials: H
authors.lastname: Brühl
authors.forename: Josef
authors.initials: J
authors.lastname: Cihak
authors.forename: Marianne
authors.initials: M
authors.lastname: Niedermeier
authors.forename: Andrea
authors.initials: A
authors.lastname: Denzel
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodriguez Gomez
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Talke
authors.forename: Nicole
authors.initials: N
authors.lastname: Goebel
authors.forename: Jirí
authors.initials: J
authors.lastname: Plachý
authors.forename: Manfred
authors.initials: M
authors.lastname: Stangassinger
authors.forename: Matthias
authors.initials: M
authors.lastname: Mack
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000503:physiopathology*; D001491:Basophils / Q000166:cytology; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D002478:Cells, Cultured; D003094:Collagen / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D007377:Interleukin-3 / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D015847:Interleukin-4 / Q000494:pharmacology; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D013154:Spleen / Q000378:metabolism; D013583:Synovial Membrane / Q000378:metabolism
chemical_list: D007377:Interleukin-3; D015850:Interleukin-6; D015847:Interleukin-4; D003094:Collagen