T-cell-specific surface glycoprotein CD28/CD28

T-cell-specific surface glycoprotein CD28, contains an Ig-like V-type domain. CD28 is one of the proteins expressed on T cells that provide co-stimulatory signals, which are required for their activation. It is the receptor for CD80 and CD86. 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. It involved in T-cell activation, the induction of cell proliferation and cytokine production and promotion of T-cell survival.