Patient-specific peptide-HLA tumor-associated antigen complex (pHLA complex) (pHLA complex)

Patient-specific peptide-HLA tumor-associated antigen complexes are the fundamental units of recognition for the adaptive immune system in oncology (Sahin & Türeci, 2018, Science). These complexes are formed when intracellular proteins, including those with tumor-specific mutations known as neoantigens, are degraded into short peptides and loaded onto Human Leukocyte Antigen (HLA) molecules for presentation on the cell surface (Ott et al., 2017, Nature). The resulting peptide-HLA (pHLA) complex acts as a ligand for T-cell receptors (TCRs), which, upon binding, initiate a targeted cytotoxic immune response against the cancer cell (Blass & Ott, 2021, Nature Reviews Clinical Oncology). Because these complexes are unique to both the individual's genetic makeup (HLA type) and the specific mutations within their tumor, they serve as the basis for highly personalized immunotherapies (Hu et al., 2021, Nature Reviews Immunology). Therapeutic strategies targeting these complexes include personalized mRNA vaccines, synthetic long peptide vaccines, and TCR-engineered T-cell therapies, all designed to prime the immune system to recognize these specific signatures. While promising, the therapeutic utility of these targets is challenged by the high degree of tumor heterogeneity and the potential for tumors to downregulate HLA expression as a mechanism of immune escape (Sahin & Türeci, 2018, Science).

Other names

Personalized neoantigensTumor-specific antigen-MHC complexespMHC complexesNeoepitopesTumor-associated antigen-HLA complexes

Induction of a specific T-cell response against tumor cells by presenting synthetic or vaccine-derived peptides on the patient's HLA molecules, thereby mimicking natural antigen presentation to activate CD8+ and CD4+ T cells (Sahin & Türeci, 2018, Science).