T-cell surface glycoprotein CD3 zeta chain (CD3ζ (also known as CD247))

T-cell surface glycoprotein CD3 zeta chain (CD3ζ or CD247) is a transmembrane protein that is an essential component of the T cell receptor (TCR)-CD3 complex, present on T lymphocytes[1][2][3][6]. The CD3ζ chain, together with other CD3 subunits (gamma, delta, epsilon), associates with TCR alpha/beta (or gamma/delta) heterodimers to form the functional TCR-CD3 complex, which is responsible for antigen recognition and signal transduction during adaptive immune responses[1][3][6][7]. The zeta chain contains three immunoreceptor tyrosine-based activation motifs (ITAMs) in its cytoplasmic domain, which become phosphorylated following TCR engagement, initiating a signaling cascade that leads to T cell activation[3][6][7]. This chain plays a critical role in immune synapse formation, T cell development, and mediating cellular immune responses[5]. Antibodies targeting CD3 (such as muromonab-CD3) are used as immunotherapeutic agents and induce T cell modulation or depletion, though their use carries the risk of significant adverse immune reactions, including cytokine release syndrome[3][6]. CD3ζ is a key biomarker for identifying and studying T cells in research and clinical diagnostics[3][6].

Other names

CD247T-cell receptor T3 zeta chainTCR zeta chainT3ZTCRZCD3 zeta chain

Monoclonal antibodies bind CD3ζ (CD247) or the entire CD3 complex, leading to T cell activation, depletion, or modulation of function - Immunotherapy: anti-CD3 binding leads to TCR signaling, cytokine release, or sometimes T cell apoptosis depending on context and formulation