Patient-specific peptide–major histocompatibility complex complex

The **patient-specific peptide–major histocompatibility complex complex** refers to unique combinations of peptides (often neoantigens derived from tumor-specific mutations or altered proteins) presented by MHC molecules on the surface of tumor cells. These complexes serve as essential immune targets, as cytotoxic T lymphocytes recognize them through their T cell receptors, leading to targeted destruction of malignant cells. Immunotherapies are being developed to enhance or exploit these patient- and tumor-specific complexes, including strategies to deliver novel peptides for presentation, engineered TCR therapies targeting such complexes, antibody-based targeting of defined peptide–MHC configurations, and even extracellular vesicle-based delivery of peptide–MHC complexes. Therapeutic success is closely linked to the presence, abundance, and specificity of these complexes, as well as intact MHC expression and antigen-presenting machinery. Challenges include MHC loss or downregulation by tumor cells, low abundance of specific complexes, and the risk of attacking normal tissues if similar complexes are present. Overall, patient-specific peptide–MHC complexes represent a promising and highly specific class of immunotherapy targets in oncology[1][2][3][4].

Other names

Peptide–MHC complexTumor-specific peptide–MHC complexNeoantigen–MHC complexPatient-specific neoantigen–MHC complex

Immune targeting of tumor cells through recognition of presented peptides by cytotoxic T lymphocytes (TCR-mediated recognition)[1][3] Direct delivery of antigenic peptides to the cytoplasm of tumor cells for enhanced surface presentation on MHC complexes, leading to increased T-cell activation[1] Antibody or fusion protein binding to specific peptide–MHC complexes on tumor cells, acting as a bridge for immune effector cell recruitment (e.g., CTLs)[3] Use of extracellular vesicle-mediated transfer of peptide-loaded MHC complexes to antigen-presenting cells or direct stimulation of T cells[2]