Tumor-associated antigen-expressing cell recognized via T cell receptor–CD3 complex (TCR–CD3 complex-mediated tumor-associated antigen recognition)

The “tumor-associated antigen-expressing malignant or infected cells via TCR/CD3 complex recognition” is not a single molecular entity, but refers to a class of cells—typically cancerous or pathogen-infected cells—that express on their surface peptides derived from mutated, overexpressed, or foreign proteins in the context of major histocompatibility complex (MHC) molecules. These peptide–MHC complexes are recognized by the T cell receptor (TCR) in conjunction with the CD3 complex on the surface of T lymphocytes. Upon antigen recognition, the TCR–CD3 complex transduces activation signals, leading to targeted immune destruction of the antigen-bearing cell[1][2][3][4][5][6]. Many modern immunotherapies—including bispecific T cell engagers and adoptive cell therapies—seek to exploit this antigen recognition machinery to direct immune responses selectively against malignant or infected cells. Therapeutic efficacy and specificity depend on the unique expression profile of the tumor- or pathogen-derived antigen and the ability of the TCR–CD3 complex to discriminate between healthy and diseased cells. However, challenges include the risk of targeting normal cells expressing similar antigens and the potential for immune-related toxicities.

Other names

Tumor cells presenting tumor-associated antigen via MHCInfected cells presenting pathogen-derived peptides via MHC to TCR–CD3TCR–CD3-recognized tumor target cells

Engagement of TCR–CD3 complex on T cells by peptide–MHC displayed on malignant/infected cells results in T cell activation, proliferation, and cytotoxicity against the target cell. Bispecific antibodies (e.g., BiTEs) tether T cells to tumor cells and exploit TCR–CD3 signaling to mediate tumor cell lysis.