CD22 Chimeric Monoclonal Antibody

CD22 is a transmembrane receptor and member of the sialic acid-binding immunoglobulin-type (Ig-type) lectin (SIGLEC) family.{65416,13652} It is composed of N-terminal extracellular Ig-like variable (IgV) and Ig-like constant 2 (IgC2) domains, a membrane-spanning region, and an intracellular immunoreceptor tyrosine-based inhibitory motif (ITIM) domain. CD22 has two isoforms formed via alternative splicing, CD22?, which is the full-length form and contains six IgC2 domains, and CD22?, which lacks the third and fourth IgC2 domains. It is expressed in the cytosol of premature B cells and on the cell surface of resting and activated B lymphocytes but is not expressed in differentiated B cells.{65417} CD22 is an inhibitory receptor activated by binding of ?2,6-linked sialic acid-containing molecules, such as glycoproteins, which stimulates phosphorylation of tyrosine in the ITIM domain, leading to recruitment of Src homology 2 domain-containing phosphatases (SHPs), including SHP-1, spleen tyrosine kinase (Syk), LYN, and PI3K.{65416,13652} Knockout of Cd22 decreases IgG1 titers in mice immunized with OVA/alum and expression of human CD22 in Cd22 -/- mice rescues this phenotype.{65418} CD22 is overexpressed in cancer cells isolated from patients with hairy cell leukemia.{65417} Cayman’s CD22 Chimeric Monoclonal Antibody was produced recombinantly from the humanized EPB-2/LL2 antibody sequence and can be used for flow cytometry (FC) and immunoprecipitation (IP) applications. The humanized EPB-2/LL2 antibody was generated by fusing human IgG1 constant domains to the antigen-binding domain of the anti-CD22 mouse monoclonal antibody, EPB-2/mLL2.{66217,66218}