Recombinant Human CD28/TP44 Protein (mFc Tag)

T-cell-specific surface glycoprotein CD28 (CD28) is a single-pass typeI membrane protein which contains one Ig-likeV-type (immunoglobulin-like) domain. It belongs to the immunoglobulin (Ig) superfamily. CD28 is one of the molecules expressed on T cells that provide co-stimulatory signals; which are required for T cell activation. CD28 co-stimulation is necessary for CD4 positive T-cell proliferation and survival; interleukin-2 production; and T-helper type-2 development. Human post-thymic regulatory T cells require CD28 co-stimulation to expand and maintain potent suppressive function in vivo. Apoptosis plays a key role in the age-related decline of CD28 expression and in immunosenescence. CD28 is the receptor for CD80 (B7.1) and CD86 (B7.2) . When activated by Toll-like receptor ligands; the CD80 expression is upregulated in antigen presenting cells (APCs) . The CD86 expression on antigen presenting cells is constitutive. CD28 is the only B7 receptor constitutively expressed on naive T cells.

Generally, lyophilized proteins are stable for up to 12 months when stored at -20 to -80°C. Reconstituted protein solution can be stored at 4-8°C for 2-7 days. Aliquots of reconstituted samples are stable at < -20°C for 3 months.