Cluster of Differentiation 3 Receptor (CD3)

The CD3 receptor, also known as the CD3 complex, is a multimeric protein complex and T cell co-receptor that plays a central role in T cell activation. It is expressed exclusively on T cells and is essential for transmitting signals from the antigen-recognizing T cell receptor (TCR) into the interior of the cell, leading to immune responses. It consists of CD3γ, CD3δ, two copies of CD3ε, and a homodimer of CD3ζ. Upon antigen recognition, ITAMs within the CD3 complex are phosphorylated, initiating downstream signaling cascades leading to T cell activation, proliferation, and differentiation. CD3 is an important therapeutic target for modulating immune responses in transplantation, autoimmunity, and cancer immunotherapy.

Other names

T-cell receptor T3 complex

CD3 antibodies bind to the CD3 receptor, leading to T cell depletion or modulation of T cell activity.