CD5, Recombinant, Human, aa25-371, His-tag (Lymphocyte antigen T1/Leu 1, p56 62, T cell surface glycoprotein CD5, T1)

CD5, also known as Leu1, Ly1, and T1, is a 67kD transmembrane glycoprotein in the scavenger receptor superfamily. Mature human CD5 consists of a 348aa extracellular domain (ECD) with three scavenger receptor cysteinerich (SRCR) domains, a 30aa transmembrane segment, and a 93aa cytoplasmic domain. Within the ECD, human CD5 shares 55% aa sequence identity with mouse and rat CD5. The 52kD ECD can be cleaved from the cell surface and circulates in the serum. CD5 has been shown to interact homophilically, with CD72 on B cells, and with betaglucan components of fungal cell walls.CD5 expression on developing thymocytes is positively regulated by signaling through the T cell antigen receptor (TCR) and is upregulated on tolerized peripheral CD4+ cells. It inhibits TCR signaling and promotes T cell nonresponsiveness and survival. CD5 signaling inhibits the generation of regulatory T cells but promotes the development of Th17 cells. Within the B cell lineage, CD5 is expressed on B1a cells, anergic B cells, and IL10 producing regulatory B cells.Similarly to on T cells, it negatively regulates signaling through the B cell antigen receptor and supports peripheral B cell survival, anergy, and tolerance. B cells can produce an intracellularly retained form of CD5 which lacks the signal peptide and a portion of the first SRCR domain. CD5 is also involved in the cellular entry of hepatitis C virus into T cells. Source: Recombinant corresponding to aa25-371 from human CD5 fused to His-tag at C-terminal expressed in NSO cell line. Molecular Weight: ~39.9kD Biological Activity: Measured by its binding ability in a functional ELISA. When Zymosan is coated at 200ug/ml (100ul/well), the concentration of recombinant human CD5 that produces 50% optimal binding response is typically 0.6-3ug/ml. Endotoxin: ~1EU/1ug (LAL) Storage and Stability: Lyophilized powder may be stored at -20 degrees C. Stable for 12 months at -20 degrees C. Reconstitute with sterile buffer. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.