T-cell surface glycoprotein CD3 epsilon chain (CD3ε) (CD3ε)

T-cell surface glycoprotein CD3 epsilon chain (CD3ε) is a vital component of the T-cell receptor (TCR) complex, essential for the transmission of activation signals into T cells [UniProt: P07766, NCBI Gene: 916]. It contains an immunoreceptor tyrosine-based activation motif (ITAM) in its cytoplasmic domain, which, upon phosphorylation, serves as a docking site for signaling molecules like ZAP-70 [UniProt: P07766, StatPearls: NBK539771]. This process is fundamental to the adaptive immune response, allowing T cells to recognize and respond to foreign antigens [StatPearls: NBK539771]. In oncology, CD3ε is frequently targeted by bispecific antibodies, such as epcoritamab, which possess one arm specific for CD3 and another for a tumor-associated antigen like CD20 [FDA Label: Epkinly]. By binding to CD3ε, these therapeutic agents physically bridge T cells to cancer cells, triggering T-cell activation and the subsequent release of perforins and granzymes to induce tumor cell lysis [FDA Label: Epkinly, PMID: 33033267]. This mechanism effectively redirects the patient's own immune system to eliminate malignant cells, particularly in B-cell lymphomas [FDA Label: Epkinly]. Beyond its role in cancer, CD3ε is critical for T-cell development in the thymus, and mutations in the gene can lead to severe combined immunodeficiency [UniProt: P07766, NCBI Gene: 916]. Therapeutic targeting of CD3ε requires careful management due to the risk of systemic inflammatory responses like cytokine release syndrome [FDA Label: Epkinly].

Other names

CD3ET-cell antigen receptor complex epsilon subunitT3ETCRECD3 epsilon

T-cell redirection and activation via the formation of a cytolytic synapse between a cytotoxic T cell and a target cell [FDA Label: Epkinly, PMID: 33033267].