Human Fc Fragment Of IgA Receptor / CD89 (FCAR) Protein

Background

The Fc alpha receptor (FCAR), also known as CD89, is a receptor protein expressed on the surface of certain immune cells, primarily neutrophils, monocytes, macrophages, and some dendritic cells. This receptor binds specifically to the Fc region of immunoglobulin A (IgA), the most abundant antibody found in mucosal secretions and an essential player in immune responses in the gastrointestinal and respiratory tracts. The interaction between CD89 and IgA is critical for initiating immune responses such as phagocytosis, cytokine production, and antibody-dependent cellular cytotoxicity (ADCC). The FCAR gene encoding CD89 is located on chromosome 19q13, and it belongs to the immunoglobulin (Ig) superfamily. The biological significance of CD89 lies in its role as a primary mediator of IgA-dependent immune mechanisms, making it essential in mucosal immunity and in the clearance of pathogens from the body.