CD89, also known as FcαR, is a 55-100kDa glycosylated protein. It belongs to the immunoglobulin gene family. It is expressed on granulocytes, monocytes, and macrophages but is absent on T cells. It can interact with IgA aggregates and plays an important role in IgA mediated immune responses. This gene is a member of the immunoglobulin gene superfamily and encodes a receptor for the Fc region of IgA. The receptor is a transmembrane glycoprotein present on the surface of myeloid lineage cells such as neutrophils, monocytes, macrophages, and eosinophils, where it mediates immunologic responses to pathogens. It interacts with IgA-opsonized targets and triggers several immunologic defense processes, including phagocytosis, antibody-dependent cell-mediated cytotoxicity, and stimulation of the release of inflammatory mediators. Multiple alternatively spliced transcript variants encoding different isoforms have been described for this gene.

Strain specific FCAR expression analysis in homozygous B-hFCAR mice by flow cytometry. 

Spleen, bone marrow and blood were collected from wild-type C57BL/6 mice (+/+)  and homozygous B-hFCAR mice (H/H), and analyzed by flow cytometry with anti-FCAR antibody. Human FCAR was detectable in NK cells of homozygous B-hFCAR mice.

Strain specific FCAR expression analysis in homozygous B-hFCAR mice by flow cytometry. 

Spleen, bone marrow and blood were collected from wild-type C57BL/6 mice (+/+)  and homozygous B-hFCAR mice (H/H), and analyzed by flow cytometry with anti-FCAR antibody. Human FCAR was detectable in monocyte of homozygous B-hFCAR mice.