Tumor-associated antigenic peptide (TAAP) (TAAP)

Tumor-associated antigenic peptides (TAAPs) are short amino acid sequences derived from proteins that are either uniquely expressed or significantly overexpressed in malignant cells compared to normal tissues (NCI Dictionary). These peptides are generated through intracellular proteasomal degradation and are subsequently presented on the cell surface by Major Histocompatibility Complex (MHC) molecules, primarily MHC Class I for CD8+ T cells and MHC Class II for CD4+ T cells (PMID: 32698311). This presentation allows the immune system to distinguish cancerous cells from healthy ones, making TAAPs the primary targets for T-cell-mediated immune surveillance (PMID: 25610163). TAAPs encompass several categories, including cancer-testis antigens (e.g., NY-ESO-1), differentiation antigens (e.g., gp100), and overexpressed self-antigens (e.g., HER2/neu) (PMID: 31439931). In modern oncology, TAAPs serve as the fundamental targets for a wide array of immunotherapies, such as peptide vaccines, TCR-engineered T-cells, and bispecific antibodies (PMID: 32453311). The therapeutic challenge lies in identifying peptides with high tumor specificity to avoid "on-target, off-tumor" toxicity, where the immune system attacks healthy tissues expressing low levels of the target antigen (PMID: 32698311). Additionally, tumors may evade immune recognition by downregulating the expression of these peptides or the MHC machinery itself (PMID: 32698311).

Other names

Tumor-associated antigenTAATumor-specific antigenTSANeoantigenCancer-testis antigenCTAOncofetal antigenDifferentiation antigenMHC-associated peptideMAP

TAAPs are presented by MHC molecules on the surface of tumor cells, where they are recognized by the T-cell receptors (TCRs) of cytotoxic T lymphocytes, leading to targeted cell lysis and the induction of a systemic anti-tumor immune response.