Recombinant Cynomolgus Siglec-2/CD22 Fc Chimera Protein, CF

Recombinant Cynomolgus Siglec-2/CD22 Fc Chimera Protein, CF Summary

Product Specifications

Product Datasheets

Carrier Free

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.

Background: Siglec-2/CD22

Siglecs are sialic acid specific I‑type lectins that are characterized by an extracellular domain (ECD) with an N‑terminal Ig‑like V-type domain followed by varying numbers of Ig‑like C2-type domains (1, 2). Siglec-2, also known as B cell antigen CD22 or B-lymphocyte cell adhesion molecule (BL-CAM), is a B cell restricted glycoprotein that is expressed in the cytoplasm of progenitor B and pre-B cells and on the surface of mature B cells. In humans, two distinct Siglec-2 cDNAs that arise from differential RNA processing of the same gene have been isolated. The predominant Siglec-2 (Isoform CD22-beta) encodes an 847 amino acid (aa) polypeptide with a hydrophobic signal peptide, an N-terminal Ig-like V-type domain, six Ig-like C2-type domains, a transmembrane region and a cytoplasmic tail with four immunoreceptor tyrosine-based inhibition motifs (ITIMs) (3). The variant Siglec-2 (Isoform CD22-alpha) encodes a 647 aa polypeptide missing two Ig-like C2-type domains and has a truncated (23 aa) cytoplasmic tail (4). Within the ECD, cynomolgus Siglec-2 shares 84%, 55%, and 56% aa sequence identity with human, mouse, and rat Siglec-2, respectively. Siglec-2 is an adhesion molecule that preferentially binds alpha 2,6- linked sialic acid on the same (cis) or adjacent (trans) cells. Interaction of Siglec-2 with trans ligands on opposing cells is found to be favored over the binding of ligands in cis (5). Consistent with a single ligand-binding region, the first two N-terminal Ig-like domains mediated CD22 adhesion with lymphocytes, neutrophils, monocytes, and erythrocytes (6). Besides its role as an adhesion molecule, Siglec-2 is a co-receptor that physically interacts with B cell receptor (BCR) and is rapidly phosphorylated upon BCR ligation. It negatively regulates BCR signals by recruiting tyrosine phosphatase SHP-1 to its ITIMs. Phosphorylated Siglec-2 can also interact with other intracellular effector proteins such as Syk, PLC gamma, PI3 kinase and Grb-2, suggesting it may play a role in positive signaling (7, 8).

Related Research Areas

• Acute Lymphoblastic Leukemia
• B Cell Activation
• B Cell Markers
• Dendritic Cell Activation
• Dendritic Cell Adhesion and Migration
• Dendritic Cell ITIM/ITAM Immunoreceptors
• Ig-type Lectins
• ITIM/ITAM Immunoreceptors and Related Molecules
• Lymphoid Lineage Markers
• Lymphoma
• Microglia Homeostasis