CD28 Antibody [37.51]

CD28 is a type I disulfide-linked homodimer that is constitutively expressed on most thymocytes, at low density on nearly all CD4+ and CD8+ peripheral T lymphocytes and at very low levels on NK cells. Its expression is upregulated upon T-cell activation. CD28 is a ligand for CD80 (B7-1) and CD86 (B7-2) on B cells and other antigen presenting cells and plays an important role in the interaction between T cells and B cells. CD28 is a costimulatory receptor involved in many, but not all, T-cell independent immune responses.