title: Intracellular Storage of Duffy Antigen-Binding Chemokines by Duffy-Positive Red Blood Cells.
abstract: BACKGROUND
  Duffy antigen/chemokine receptor (DARC) is a non-signaling receptor for multiple chemokines. The role of DARC on red blood cells (RBCs) has remained elusive. The purpose of this study was to analyze selective storage of DARC-binding chemokines in RBCs.
  
  
  METHODS
  Peripheral blood from healthy volunteers with DARC-positive blood type was collected in EDTA tubes. The concentration of DARC binding chemokines (i.e., MCP-1, RANTES, eotaxin-1, TARC, and IL-8), DARC nonbinding chemokines (i.e., MIP-1α, IP-10), and several cytokines in the supernatant of purified RBCs before and after hemolysis was measured using Bio-Plex and ELISA assays. Storage of chemokines in RBCs and the expression of DARC were evaluated using flow-cytometry.
  
  
  RESULTS
  The levels of all DARC-binding chemokines except TARC and IL-8 increased significantly after hemolysis. There was no significant increase in any of the DARC non-binding chemokines or in the other cytokines after hemolysis. RANTES, eotaxin-1, and MCP-1 were detectable intracellularly but not on the RBC surface. RANTES was absorbed by RBCs. DARC was expressed intracellularly in RBCs as well as on the surface.
  
  
  CONCLUSIONS
  These data suggested that DARC-positive RBCs store RANTES, MCP-1 and eotaxin-1. DARC on RBC may be internalized from the surface in the process of chemokine absorption.
authors.forename: Ayako
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Norihiro
authors.initials: N
authors.lastname: Saito
authors.forename: Shu
authors.initials: S
authors.lastname: Ogasawara
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Shiratori
authors.forename: Jun
authors.initials: J
authors.lastname: Kondo
authors.forename: Masamichi
authors.initials: M
authors.lastname: Itoga
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kayaba
mesh_terms: D002352:Carrier Proteins; D054413:Chemokine CCL11; D018925:Chemokines; D004375:Duffy Blood-Group System; D004912:Erythrocytes; D006801:Humans; D016209:Interleukin-8; D011956:Receptors, Cell Surface
chemical_list: D002352:Carrier Proteins; D054413:Chemokine CCL11; D018925:Chemokines; D004375:Duffy Blood-Group System; D016209:Interleukin-8; D011956:Receptors, Cell Surface