Anti-CD28 Antibody, clone 37.51 clone 37.51, from hamster(Syrian)

T-cell-specific surface glycoprotein CD28 (UniProt: P31041, also known as CD28) is encoded by the Cd28 gene (Gene ID: 12487) in murine species. CD28 is a single-pass type I membrane protein that exists as a disulfide linked homodimer. In human CD28 is expressed by a majority of T cells in the periphery, including all CD4+ cells and about 50% CD8+ cells. CD28 is synthesized with a signal peptide (aa 1-19), which is subsequently cleaved off in the mature form. It has an extracellular domain (aa 2-150), a transmembrane domain (aa 151-177), and a cytoplasmic domain (aa 178-218). CD28 is involved in T-cell activation, the induction of cell proliferation and cytokine production and promotion of T-cell survival. It enhances the production of IL-4 and IL-10 in T-cells in conjunction with TCR/CD3 ligation and CD40L co-stimulation. B7-1 (CD80) and B7-2 (CD86) are two known ligands of CD28 on activated B cells and antigen presenting cells (APC). These ligands trigger CD28 signaling in concert with TCR activation to drive T cell proliferation, induce high-level expression of IL-2, impart resistance to apoptosis, and enhance T cell cytotoxicity. The interaction co-stimulatory signaling between the B7 ligands and CD28 is essential for crucial communication between T cells and B cells or APCs to coordinate the adaptive immune response.