CD28 Proteins

Protein Information

CD28 antigen is a 44 kDa disulfide linked homodimeric T cell specific surface glycoprotein. CD28 is a cell adhesion molecule of the immunoglobulin superfamily which is constitutively expressed on most peripheral blood T lymphocytes. Moreover, CD28 is the critical T cell costimulatory receptor that provides the cell the important second activation signal by binding CD80 and CD86 which are expressed by antigen presenting cells. In addition to its co-stimulation role, CD28 functions by preventing T cells from entering an anergic-hyporesponsive state or from undergoing premature apoptotic cell death. In murine peripheral lymphoid organs and in the blood, all CD4+ and CD8+ T cells express CD28. In the thymus, CD28 expression is highest on immature CD3-, CD8+ and CD4+8+ cells, and on CD4-8- cells that express alpha/beta and gamma/delta TCR. The level of CD28 on mature CD4+ and CD8+ alpha/beta TCR+ thymocytes is two- to fourfold lower than on the immature cells. Diseases associated with CD28 dysfunction include mycosis fungiodes and Sezary's Disease.

Synonyms

antigen CD28; Cd28; CD28 antigen; CD28 antigen (Tp44); CD28 isoform; CD28 isoform 2; CD28 molecule; CD28 precursor protein; CD28 protein; CD28 protein precursor; CD28RNA; cell surface protein; CHT28; contains partial extracellular domain; costimulatory molecule B7 receptor CD28; EGK_04709; MGC138290; sCD28; soluble CD28; T44; T-cell costimulatory molecule CD28; T-cell costimulatory molecule Tp44; T-cell-specific surface glycoprotein CD28; T-cell-specific surface glycoprotein CD28 homolog; TP44