Neote K, Mak J Y, Kolakowski L F, Schall T J
Department of Immunology, Genentech Inc, South San Francisco, CA.
Blood. 1994 Jul 1;84(1):44-52.
The Duffy blood group antigen has been postulated to be a receptor on red blood cells (RBCs) for the malarial parasite Plasmodium vivax and a promiscuous receptor for the chemokine superfamily of inflammatory proteins. Recently, the Duffy antigen glycoprotein D cDNA has been cloned (Chaudhuri et al: Proc Natl Acad Sci USA 90:10793, 1993). We have analyzed the binding properties of the cloned Duffy antigen. Duffy-antigen cDNAs expressed in human embryonic kidney cells produced cell-surface proteins that reacted with two known anti-Duffy monoclonal antibodies. Direct ligand binding and displacement experiments using recombinant chemokine proteins also show that the cloned Duffy protein is the RBC chemokine receptor. Radiolabeled chemokines of both the C-C (RANTES and MCP-1) and C-X-C (IL-8 and MGSA/gro) subclasses bound reversibly to transfected cells with dissociation constants in the nanomolar range. Chemokines of either class displaced heterologous chemokines, indicating that they were competing for a single site on the transfected cells. Although the chemokines bound to the transfected cells with high affinity, there was no evidence for signal transduction, as measured by transient increases in intracellular calcium ion concentration, through the Duffy antigen/RBC chemokine receptor in transfected cells. Lastly, we have performed a computer analysis on the amino acid structure of the Duffy antigen/RBC chemokine receptor. Although the cloned Duffy antigen has been postulated to be a nine-transmembrane-spanning receptor, our analysis suggests that the molecule most likely belongs to the seven-transmembrane-spanning receptor superfamily and is therefore similar to other chemokine receptors previously identified.
达菲血型抗原被推测为间日疟原虫在红细胞（RBC）上的受体以及炎症蛋白趋化因子超家族的一种多配体受体。最近，达菲抗原糖蛋白D的cDNA已被克隆（Chaudhuri等人：《美国国家科学院院刊》90:10793，1993年）。我们分析了克隆的达菲抗原的结合特性。在人胚肾细胞中表达的达菲抗原cDNA产生了与两种已知抗达菲单克隆抗体发生反应的细胞表面蛋白。使用重组趋化因子蛋白进行的直接配体结合和置换实验也表明，克隆的达菲蛋白是红细胞趋化因子受体。C-C（RANTES和MCP-1）和C-X-C（IL-8和MGSA/gro）亚类的放射性标记趋化因子均以纳摩尔范围内的解离常数可逆地结合到转染细胞上。任一类型的趋化因子都能置换异源趋化因子，这表明它们在竞争转染细胞上的单个位点。尽管趋化因子以高亲和力结合到转染细胞上，但在转染细胞中，通过达菲抗原/红细胞趋化因子受体，未观察到通过细胞内钙离子浓度短暂升高所测量的信号转导证据。最后，我们对达菲抗原/红细胞趋化因子受体的氨基酸结构进行了计算机分析。尽管克隆的达菲抗原被推测为一种九次跨膜受体，但我们的分析表明，该分子很可能属于七次跨膜受体超家族，因此与先前鉴定的其他趋化因子受体相似。
