Ionic liquid–mediated cellular loading for whole tumor cell vaccines

Conventional whole tumor cell cancer vaccines have demonstrated limited clinical success due to insufficient immunogenicity and challenges in adjuvant codelivery, despite their rich antigen repertoire and high patient-specific activity. Here, we introduce a simple, single-step approach to load immunostimulatory CpG oligodeoxynucleotides into tumor cells undergoing immunogenic cell death using an ionic liquid–containing cocktail. Results indicate that these adjuvant-loaded tumor cells (referred to as IL-Vax) enhance the uptake of cell-based vaccines by dendritic cells and their subsequent activation, leading to potent antitumor immunity. IL-Vax offered strong protection against tumor growth in a prophylactic B16F10 melanoma mouse model. Furthermore, IL-Vax synergized with PD-1 blockade to slow tumor growth and extend survival in a therapeutic model. The modularity of IL-Vax enables the loading of different cargos or cargo combinations, which may be conducive for additional tailoring of such vaccines and potentially other cell loading applications.