Tumor Antigens and CD3 (CD3)

Tumor antigens are molecules (often proteins or peptides) abnormally expressed or mutated in tumor cells and recognized by the immune system; prominent subclasses include tumor-associated and tumor-specific antigens such as cancer-testis antigens (e.g., MAGE family, PRAME). CD3 is a multimeric protein complex associated with the T cell receptor, essential for T cell activation and downstream signaling; it consists of multiple subunits (CD3ε, γ, δ, and ζ) and is present on all mature T cells. Modern immunotherapies, such as bispecific antibodies and TCR-engineered T cells, leverage the specificity of tumor antigen recognition and the potent immune activation conferred by CD3 to redirect and amplify anti-tumor immunity. The combination of tumor antigen targeting and CD3 crosslinking underlies several transformative cancer therapies but also poses significant safety and selectivity challenges.

Other names

CD3 complexT cell receptor-CD3 complexT3 complexCancer-testis antigenstumor-associated antigenstumor-specific antigensCTATAATSA

Bispecific antibodies link CD3 on T cells to tumor antigens on cancer cells, redirecting T cell cytotoxicity toward tumor cells. Engineered T cell receptors (TCRs) recognize peptide-MHC complexes of tumor antigens and activate T cells via associated CD3 signaling. Vaccine strategies induce immune responses against tumor antigens.