Maliszewski C R, March C J, Schoenborn M A, Gimpel S, Shen L
Immunex Corporation, Seattle, Washington 98101.
J Exp Med. 1990 Dec 1;172(6):1665-72. doi: 10.1084/jem.172.6.1665.
IgA, the predominant isotype in secretions, mediates the neutralization and removal of environmental antigens from mucosal sites. Although cell surface receptors for the Fc region of IgA (Fc alpha R) have been implicated in a variety of immune effector mechanisms, the molecular features of Fc alpha R remain only marginally characterized. In this report, we describe the isolation of a clone from a myeloid cell line cDNA library that directs the expression of a cell surface molecule with IgA binding specificity. The cDNA encodes a peptide of Mr 30,000 including a putative transmembrane region with features atypical of conventional membrane-anchored proteins. Databank searches indicate that the human myeloid cell Fc alpha R sequence is unique, is a member of the immunoglobulin gene superfamily, and is related to Fc receptors for IgG (Fc gamma RI, II, and III) and IgE (Fc epsilon RI).
IgA是分泌物中的主要同种型，介导从黏膜部位中和并清除环境抗原。尽管IgA的Fc区细胞表面受体（FcαR）参与了多种免疫效应机制，但FcαR的分子特征仍未得到充分表征。在本报告中，我们描述了从髓样细胞系cDNA文库中分离出一个克隆，该克隆指导表达具有IgA结合特异性的细胞表面分子。该cDNA编码一个30000 Mr的肽，包括一个具有非传统膜锚定蛋白特征的假定跨膜区域。数据库搜索表明，人类髓样细胞FcαR序列是独特的，是免疫球蛋白基因超家族的成员，并且与IgG（FcγRI、II和III）和IgE（FcεRI）的Fc受体相关。
