Th1-biased iNKT cell agonist-loaded liposomal peptide vaccines synergize with a PD-L1 inhibitor to boost immunotherapy against gastric cancer.

We covalently conjugated the Th epitope DT331-345 with the MG3 peptide and co-encapsulated the conjugate with an iNKT cell agonist into liposomes to prepare a vaccine. The DT-MG3/GCS-11 formulation elicited strong antibody responses and promoted T-cell responses. Notably, its combination with PD-L1 inhibitor BMS-202 suppressed tumor growth and prolonged the survival in tumor-bearing mice.