Anti-CD22 Antibody[LL2]

CD22 is a 130 kD type I transmembrane glycoprotein also known as Siglec-2 and BL-CAM. It is a member of the immunoglobulin superfamily (sialoadhesion subgroup). CD22 is expressed in the cytoplasm of pro-B and pre-B cells, and on the surface of mature B and activated B cells, but not on plasma cells. CD22 is present in the B cell receptor complex and associates with SHP-1, Syk, Lck, Lyn, and phospholipase Cgamma1. A primary function of CD22 is thought to be in limiting antigen receptor signaling by modulating B cell activation threshold. CD22 has been shown to bind to CD45RO and CD75, although the natural ligands for this molecule remain controversial. 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]