Tumor-derived or pathogen-derived antigenic peptide (Antigenic peptide)

Tumor-derived or pathogen-derived antigenic peptides are short amino acid sequences, typically 8 to 15 residues in length, that result from the intracellular proteolysis of proteins and are subsequently presented on the cell surface by Major Histocompatibility Complex (MHC) molecules. In oncology, these peptides include neoantigens derived from somatic mutations and tumor-associated antigens derived from overexpressed or lineage-specific proteins, which serve as specific markers for immune recognition. Pathogen-derived peptides are similarly processed from viral or bacterial proteins during the course of an infection to signal the presence of non-self entities to the adaptive immune system. These peptides are critical targets for modern immunotherapy, including personalized cancer vaccines and engineered T-cell receptor (TCR) therapies, which aim to direct the host's cytotoxic T-cells to eliminate diseased cells. The clinical utility of these targets depends heavily on the patient's specific HLA genotype and the stability of the peptide-MHC complex. Despite their high specificity, challenges such as tumor heterogeneity and the evolution of antigen-loss variants remain significant hurdles in therapeutic development.

Other names

NeoantigenTumor-associated antigen (TAA)Tumor-specific antigen (TSA)MHC-restricted peptideEpitopePathogen-associated antigenCancer-testis antigen (CTA)

Antigenic peptides are presented by Major Histocompatibility Complex (MHC) molecules on the cell surface to be recognized by T-cell receptors (TCRs). Therapeutic interventions such as vaccines introduce these peptides (or their genetic precursors) to prime and expand antigen-specific cytotoxic T-lymphocytes, while adoptive cell therapies like TCR-T cells are engineered to directly bind these peptide-MHC complexes, leading to the targeted lysis of the tumor or infected cell.