Anti-AF/LE Purified Anti-Mouse CD22, clone Cy34.1

The Cy34.1 monoclonal antibody specifically binds to the B-lymphocyte differentiation antigen CD22 on strains having the Lyb-8.2 alloantigen (e.g., A, BALB/c, CBA, C3H/He, C57BL, C57L, C58, SJL, SWR, but not AKR, DBA/1, DBA/2, NZB, PL). CD22 is expressed at high levels on mature peripheral B lymphocytes (follicular and marginal zone), B-1 cells (CD5+ B cells), and plasma cells. It is a member of the Ig gene superfamily and associates with the B-cell antigen receptor. Its sialic acid- binding immunoglobulin-like lectin (siglec) extracellular region mediates B-cell adhesion to ligands on endothelial cells in the bone marrow. Its intracellular domain is phosphorylated after cross-linking of antigen receptor or MHC class II antigen. It is involved in negative regulation of B-cell activation and protection from autoimmunity. B-cell proliferative responses to LPS or anti-mouse Ig chain are augmented in the presence of Cy34.1 mAb. Protein function: Mediates B-cell B-cell interactions. May be involved in the localization of B-cells in lymphoid tissues. Binds sialylated glycoproteins, one of which is CD45. Preferentially binds to alpha-2,6- linked sialic acid. The sialic acid recognition site can be masked by cis interactions with sialic acids on the same cell surface. Upon ligand induced tyrosine phosphorylation in the immune response seems to be involved in regulation of B-cell antigen receptor signaling. Plays a role in positive regulation through interaction with Src family tyrosine kinases and may also act as an inhibitory receptor by recruiting cytoplasmic phosphatases via their SH2 domains that block signal transduction through dephosphorylation of signaling molecules. [The UniProt Consortium]