Cluster of Differentiation 3 Receptor Complex (None)

The CD3 receptor complex is a multimeric protein assembly that forms an essential part of the T-cell receptor (TCR) complex on the surface of T lymphocytes. It plays a critical role in mediating signal transduction following antigen recognition, thereby initiating T cell activation and immune responses. It is composed of CD3γ, CD3δ, two CD3ε chains, and a CD3ζζ homodimer. While antigen binding occurs at the variable region of αβ or γδ TCRs, intracellular signaling is mediated exclusively by ITAM motifs present on cytoplasmic tails of all four types of invariant chains—CD3γ, δ, ε (one ITAM each), and ζ (three ITAMs per chain). Because it provides one of two primary signals required for full lymphocyte activation, targeting components like anti-CD3 antibodies can modulate immune activity.

Modulation of T cell activation via antibody binding and ITAM signaling interference or redirection