Purity: > 90% by SDS - PAGE Format: Liquid. In Phosphate Buffered Saline (pH 7.4) containing 10% glycerol.. CD28, also known as T-cell-specific surface glycoprotein CD28 isoform 1, is one of the proteins expressed on T cells that provide co-stimulatory signals required for T cell activation and survival. T cell stimulation through CD28 in addition to the T-cell receptor (TCR) can provide a potent signal for the production of various interleukins (IL-6 in particular). CD28/B7 interaction has been shown to prevent apoptosis of activated T cells via the up-regulation of bcl-XL. It ligation has also been shown to regulate Th1/Th2 differentiation. Recombinant human CD28, fused to hIgG-His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.