Human T-Cell-Specific Surface Glycoprotein CD28 (CD28) Protein

Background

CD28 is a pivotal co-stimulatory molecule expressed on the surface of T cells. It plays a crucial role in the activation and survival of T cells, which are essential components of the adaptive immune system. CD28 is predominantly found on CD4+ T helper cells, although it is also present on a subset of CD8+ cytotoxic T cells. The interaction of CD28 with its ligands, CD80 (B7-1) and CD86 (B7-2), on antigen-presenting cells (APCs) provides the necessary secondary signals that, together with signals from the T cell receptor (TCR), lead to full T cell activation, proliferation, and differentiation. The presence and function of CD28 are vital for initiating effective immune responses and for maintaining T cell homeostasis and tolerance.