Anti-CD22

CD22,also known as Siglec-2 (sialic acid binding Ig-like lectin 2) or BL-CAM (B-lymphocyte cell adhesion molecule),is a 130-140 kDa,B-cell restricted,type I transmembrane glycoprotein belonging to the immunoglobulin gene superfamily. The expression of CD22 is developmentally regulated. It is expressed at low levels in the cytoplasm of pro-B and pre-B cells and present on the cell surface only at mature stages of B-cell differentiation. Cell surface expression is lost during terminal differentiation into plasma cell and after B-cell activation. CD22 is an inhibitory receptor for B-cell receptor (BCR) signalling,preferentially binds to alpha-2,6-linked sialic acid and mediates B-cell B-cell interactions. It plays a crucial role in activation and differentiation of the B-cell. Protein function: Most highly expressed siglec (sialic acid-binding immunoglobulin-like lectin) on B-cells that plays a role in various aspects of B-cell biology including differentiation, antigen presentation, and trafficking to bone marrow (PubMed:34330755, PubMed:8627166). Binds to alpha 2,6-linked sialic acid residues of surface molecules such as CD22 itself, CD45 and IgM in a cis configuration. Can also bind to ligands on other cells as an adhesion molecule in a trans configuration (PubMed:20172905). Acts as an inhibitory coreceptor on the surface of B-cells and inhibits B-cell receptor induced signaling, characterized by inhibition of the calcium mobilization and cellular activation. Mechanistically, the immunoreceptor tyrosine-based inhibitory motif domain is phosphorylated by the Src kinase LYN, which in turn leads to the recruitment of the protein tyrosine phosphatase 1/PTPN6, leading to the negative regulation of BCR signaling (PubMed:8627166). If this negative signaling from is of sufficient strength, apoptosis of the B-cell can be induced (PubMed:20516366). [The UniProt Consortium]