title: 1α,25-dihydroxyvitamin D3 promotes CD200 expression by human peripheral and airway-resident T cells.
abstract: BACKGROUND
  CD200, a cell-surface immunoglobulin-like molecule expressed by immune and stromal cells, dampens the pro-inflammatory activity of tissue-resident innate cells via its receptor, CD200R. This interaction appears critical for peripheral immune tolerance, particularly in the airways where excessive inflammation is undesirable. Vitamin D contributes to pulmonary health and promotes regulatory immune pathways, therefore its influence on CD200 and CD200R was investigated.
  
  
  METHODS
  CD200 and CD200R expression were assessed by qPCR and immunoreactivity of human lymphoid, myeloid and epithelial cells following 1α,25-dihydroxyvitamin D3 (1α,25VitD3) exposure in vitro and in peripheral T cells following 1α,25VitD3 oral ingestion in vivo. The effect of 1α25VitD3 was also assessed in human airway-resident cells.
  
  
  RESULTS
  1α25VitD3 potently upregulated CD200 on peripheral human CD4+ T cells in vitro, and in vivo there was a trend towards upregulation in healthy, but not asthmatic individuals. CD200R expression was not modulated in any cells studied. CD200 induction was observed to a lesser extent in CD8+ T cells and not in B cells or airway epithelium. T cells isolated from the human airway also responded strongly to 1α25VitD3 to upregulate CD200.
  
  
  CONCLUSIONS
  The capacity of 1α,25-dihydroxyvitamin D3 to induce CD200 expression by peripheral and respiratory tract T cells identifies an additional pathway via which vitamin D can restrain inflammation in the airways to maintain respiratory health.
authors.affiliation: MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, Guy's Hospital, London, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Dimeloe
authors.forename: David F
authors.initials: DF
authors.lastname: Richards
authors.forename: Zoe L
authors.initials: ZL
authors.lastname: Urry
authors.forename: Atul
authors.initials: A
authors.lastname: Gupta
authors.forename: Victoria
authors.initials: V
authors.lastname: Stratigou
authors.forename: Sophie
authors.initials: S
authors.lastname: Farooque
authors.forename: Sejal
authors.initials: S
authors.lastname: Saglani
authors.forename: Andrew
authors.initials: A
authors.lastname: Bush
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Hawrylowicz
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics*; D001249:Asthma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D002648:Child; D005434:Flow Cytometry; D006801:Humans; D007108:Immune Tolerance / Q000235:genetics* / Q000276:immunology; D007111:Immunity, Cellular / Q000235:genetics; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics*; D020545:Respiratory Mucosa / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D015854:Up-Regulation; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000494:pharmacology; D014815:Vitamins / Q000494:pharmacology
chemical_list: D015703:Antigens, CD; D012333:RNA, Messenger; D014815:Vitamins; C118756:dihydroxy-vitamin D3; D014807:Vitamin D; C042739:antigens, CD200