Characterization of the human myeloid IgA Fc receptor I (CD89) gene in a cosmid clone

• Published in: Immunogenetics (New York) 1999-06, Vol.49 (6), p.586-589
• Main Authors: van Vuuren, A J, van Egmond, M, Coenen, M J, Morton, H C, van de Winkel, J G
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Antigens, CD - genetics; Base Sequence; Cloning, Molecular; Cosmids; DNA, Complementary; Humans; Immunoglobulin A; Molecular Sequence Data; Receptors, Fc - genetics
• ISSN: 0093-7711; 1432-1211
• DOI: 10.1007/s002510050544

In humans, IgA is the most prominent immunoglobulin (Ig) class present in external secretions and is postulated to play an important role in mucosal defence. The leukocyte IgA Fc receptor I (CD89) is expressed on cells of the myeloid lineage as a glycosylated transmembrane protein. On neutrophils and monocytes, CD89 represents a 55,000 to 75,000 M sub(r) protein, and on eosinophils, CD89 is expressed as a protein of 70,000 to 100,000 M sub(r). The CD89 cDNA encodes a protein of approximately 30,000 M sub(r) with six potential N-glycosylation sites (Maliszewski et al. 1990). CD89 can initiate a multitude of effector functions, including phagocytosis of IgA-opsonized particles, antibody-dependent cellular cytotoxicity, degranulation, superoxide production, and secretion of both pro- and anti-inflammatory mediators. Association of CD89 with the FcR gamma chain signalling molecule has been shown to be crucial for its biological function (Morton et al. 1996a). In contrast to other human Fc receptor genes, clustered on chromosome (Chr) 1, the gene for CD89 has been mapped to Chr 19q13.4 (Kremer et al. 1992).