Human B-Cell Receptor CD22 / SIGLEC2 (CD22) Protein

Background

CD22, also known as Siglec-2, is a member of the sialic acid-binding immunoglobulin-like lectins (Siglec) family and is predominantly expressed on B cells. It plays a crucial role in modulating B-cell receptor (BCR) signaling and maintaining B-cell tolerance, making it an essential molecule in the regulation of the immune system. CD22 is primarily found on mature B cells, acting both as an inhibitory coreceptor to dampen BCR signaling and as an adhesion molecule involved in cell-cell interactions. CD22 is essential for maintaining the delicate balance between immune activation and tolerance, preventing excessive immune responses that could lead to autoimmune diseases. It is an inhibitory receptor that modulates B-cell activity by recruiting SHP-1, a phosphatase that negatively regulates B-cell signaling pathways. In this capacity, CD22 fine-tunes the immune response to antigens, ensuring that B cells are appropriately activated and preventing autoimmunity.