title: A flow cytometric method for determination of the interferon receptor IFNAR2 subunit in peripheral blood leukocyte subsets.
abstract: BACKGROUND
  It is expected that expression levels in the peripheral blood mononuclear cells (PBMC) of IFNAR2, a subunit of the interferon (IFN) receptor, may be a marker for predicting IFN response. In the present study, we have established a rapid and convenient method for assaying IFNAR2, using flow cytometry.
  
  
  METHODS
  Fifty microliters of whole blood from healthy volunteers was treated with an anti-IFNAR2 antibody and stained with a Fluorescein isothiocyanate (FITC)-conjugated secondary antibody. In addition, the cells were stained with subset-specific antibodies conjugated with phycoerythrin (PE) and PE covalently linked to cyanin 5 at the same time. The mean FITC-fluorescence intensities were analyzed separately by gating on subset-specific regions.
  
  
  RESULTS
  IFNAR2 was detected in most lymphocytes, monocytes, and granulocytes, although IFNAR2 expression was higher in the monocytes and granulocytes than in the lymphocytes. The intra- and interdaily variations of IFNAR2 in lymphocytes, monocytes, and granulocytes were small. Among the lymphocyte subsets, IFNAR2 showed high expression in natural killer (NK) cells and low expression in T lymphocytes. The effect of IFN-alpha on IFNAR2 expression was examined in vitro. A down-regulation of IFNAR2 was observed by IFN-alpha above 100 IU/ml.
  
  
  CONCLUSIONS
  This assay may be useful for examining IFNAR2 in various leukocyte subsets, separately, as well as providing a rapid and easy method for monitoring expression of type I IFN receptors.
authors.affiliation: Research Institute of Pharmacological and Therapeutical Development, Otsuka Pharmaceutical Co., Ltd., 463-10 Kagasuno Kawauchi-cho Tokushima 771-0192, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Tochizawa
authors.forename: Seiji
authors.initials: S
authors.lastname: Akamatsu
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sugiyama
authors.forename: Masahiro
authors.initials: M
authors.lastname: Muraguchi
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Ohmoto
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Ono
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Akira
authors.initials: A
authors.lastname: Tanigami
authors.forename: Takumi
authors.initials: T
authors.lastname: Sumida
authors.forename: Toyoki
authors.initials: T
authors.lastname: Mori
mesh_terms: D005434:Flow Cytometry / Q000379:methods*; D016650:Fluorescein-5-isothiocyanate; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology; D015640:Ion Channel Gating; D007962:Leukocytes / Q000378:metabolism*; D016131:Lymphocyte Subsets; D008565:Membrane Proteins; D010799:Phycoerythrin; D053633:Receptor, Interferon alpha-beta; D017471:Receptors, Interferon / Q000378:metabolism*
chemical_list: C508033:IFNAR2 protein, human; D016898:Interferon-alpha; D008565:Membrane Proteins; D017471:Receptors, Interferon; D010799:Phycoerythrin; D053633:Receptor, Interferon alpha-beta; D016650:Fluorescein-5-isothiocyanate