Programmed death-ligand 1-derived peptide:Major Histocompatibility Complex (PD-L1 peptide:MHC) (PD-L1 peptide:MHC)

The Programmed death-ligand 1-derived peptide:Major Histocompatibility Complex (PD-L1 peptide:MHC) is an immunological target formed when intracellularly processed fragments of the PD-L1 protein are presented on the cell surface by Major Histocompatibility Complex molecules [PMID: 23447590]. While PD-L1 is widely recognized as an immune checkpoint ligand that inhibits T cells, these specific peptide-MHC complexes act as antigens that can be recognized by a unique population of proinflammatory, PD-L1-specific T cells [PMID: 30545345]. In the tumor microenvironment, PD-L1 is frequently overexpressed by both malignant cells and regulatory immune cells, such as myeloid-derived suppressor cells, making this complex a strategic target for immunotherapy [PMID: 29316948]. Therapeutic vaccines like IO103 utilize PD-L1-derived peptides to stimulate and expand these specific T cells in cancer patients [PMID: 35046180]. Once activated, these T cells target and eliminate cells expressing the PD-L1 peptide:MHC complex, thereby providing a dual benefit of direct tumor cell killing and the reduction of local immunosuppression [IO Biotech, 2023]. This approach is currently being investigated in clinical trials, often in combination with PD-1/PD-L1 inhibitors to synergistically enhance anti-tumor immunity.

Other names

PD-L1 epitope:MHC complexPD-L1-derived peptide:HLA complexPD-L1 peptide-MHCPDL1-specific T-cell target

Induction and activation of PD-L1-specific cytotoxic T lymphocytes (CTLs) that recognize the PD-L1-derived peptide presented on MHC molecules, resulting in the direct lysis of PD-L1-expressing tumor cells and immunosuppressive cells in the tumor microenvironment.