Fig. 1

Schematics of TCR-peptide/MHC interactions. In human, 95% of T cells express a pair of TCR α and β chains with six CD3 chains (CD3γ, CD3δ, 2 CD3ε, and 2 CD3ζ) and CD8 or CD4 co-receptors on the cell surface. Each CD3 chain contains one to three ITAMs at the intracellular domain. After encountering the antigen-specific peptide/MHCs expressed on the surface of tumor cells, T cells activate ITAMs, ZAP70, PKC, MAPK, NF-κB signaling pathways, and secret perforin, granzymes, and cytokines, leading to the lysis of tumor cells. ITAMs, immunoreceptor tyrosine-based activation motifs; ZAP70, Syk family kinase zeta-activated protein 70 kDa; MAPK, mitogen-activated protein kinase; PKC, protein kinase C; NF-ƙB, nuclear factor kappa-light-chain-enhancer of activated B cells; LCK, lymphocyte-specific protein tyrosine kinase