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

Programmed death-ligand 1-derived peptide-Major Histocompatibility Complex (PD-L1-MHC) complexes are molecular targets formed when the PD-L1 protein is intracellularly processed into short peptides and presented on the cell surface by MHC molecules, typically HLA-A2 (Munir et al., 2013, Cancer Research). While PD-L1 is widely known as a ligand that inhibits T-cell activity via the PD-1 receptor, these peptide-MHC complexes serve as antigens that can be recognized by a specific subset of naturally occurring proinflammatory T cells (Andersen, 2018, Cancer Immunology, Immunotherapy). In the tumor microenvironment, PD-L1 is often overexpressed by both malignant cells and immunosuppressive myeloid cells to evade immune detection. Therapeutic strategies, such as the IO103 peptide vaccine, aim to activate or expand PD-L1-specific cytotoxic T cells that recognize these complexes, thereby directly lysing PD-L1-positive cells (IO Biotech, 2024). This approach effectively turns a mechanism of immune suppression into a target for immune-mediated destruction, potentially synergizing with standard checkpoint inhibitors to overcome resistance (Kjeldsen et al., 2021, Nature Communications).

Other names

PD-L1 peptide-HLA complexHLA-presented PD-L1 epitopesPD-L1-derived antigen-MHC complexPD-L1-specific T-cell target

Vaccination with PD-L1-derived peptides induces the expansion of specific CD8+ and CD4+ T cells that recognize the PD-L1-MHC complex on the surface of target cells, leading to direct cell lysis and modulation of the tumor microenvironment.