Description: The eBio4KB128 monoclonal antibody recognizes human CD22 (Siglec-2), which is a member of the siglec subgroup of the Ig superfamily. CD22 is a type I transmembrane glycoprotein composed of two polypeptide chains, CD22α and CD22β, of 130 and 140 kDa respectively, produced by alternative splicing of the CD22 gene. CD22 is expressed at high levels on mature B cells and B cell lymphomas. The extracellular portion of CD22 contains seven Ig-like domains, some of which are capable of binding ligands with sialic acid moieties expressed on epithelial, endothelial, B and T cells. The intracellular portion of CD22 contains 6 tyrosine residues contained within immunotyrosine-based inhibitory motifs (ITIM) and immunotyrosine-based activation-like motifs, which are phosphorylated upon B-cell receptor engagement, which enables CD22 to participate in the positive and negative regulation of B-cell receptor signaling.