Specificity:

Anti-Mouse CD28 recognizes the CD28 co-stimulatory receptor, a ligand of CD80 (B7-1) and CD86 (B7-2). CD28 is important for transmitting co-stimulatory signals for optimal T-cell activation.

Anti-CD28 is present on most thymocytes, CD4+, CD8+ T-cells. The 37.51 antibody augments proliferation and IL-2 production by activated T-cells.

Background:

CD28 (Cluster of Differentiation 28) is one of the molecules expressed on T cells that provide co-stimulatory signals, which are required for T cell activation. CD28 is composed of a single Ig V-like extracellular domain, a transmembrane domain and an intracellular domain. It is expressed on the cell surface as disulfide-linked homodimer or as monomer. CD28 is the receptor for B7.1 (CD80) and B7.2 (CD86). When activated by Toll-like receptor ligands, the B7.1 expression is upregulated in antigen presenting cells (APCs). The B7.2 expression on antigen presenting cells is constitutive. CD28 is the only B7 receptor constitutively expressed on naive T cells. Stimulation through CD28 in addition to the TCR can provide a potent co-stimulatory signal to T cells for the production of various interleukins (IL-2 and IL-6 in particular). CD28 possesses an intracellular domain with several residues that are critical for its effective signalling. CD28 also contains two proline-rich motifs that are able to bind SH3-containing proteins.

CD28 has also been found to stimulate eosinophil granulocytes where its ligation with anti-CD28 leads to the release of IL-2, IL4, IL-13 and IFN-γ.

Allophycocyanin (APC) has a molecular weight of 104 kDa and is purified from green algae. APC is an intensely bright phycobiliprotein with a broad absorption profile that peaks at ~650 nm, and a fluorescence emission maximum of ~660 nm.

Known Species Cross Reactivity: Ms+