Co-Delivery of the Human NY-ESO-1 Tumor-Associated Antigen and Alpha-GalactosylCeramide by Filamentous Bacteriophages Strongly Enhances the Expansion of Tumor-Specific CD8+ T Cells

Abstract: Tumor-associated antigens (TAAs) represent attractive targets in the development of anti-cancer vaccines. The filamentous bacteriophage is a safe and versatile delivery nanosystem, andrecombinant bacteriophages expressing TAA-derived peptides at a high density on the viral coatproteins improve TAA immunogenicity, triggering effective in vivo anti-tumor responses. Toenhance the efficacy of the bacteriophage as an anti-tumor vaccine, we designed and generatedphage particles expressing a CD8+ peptide derived from the human cancer germline antigen NY-ESO-1 decorated with the immunologically active lipid alpha-GalactosylCeramide (?-GalCer), apotent activator of invariant natural killer T (iNKT) cells. The immune response to phage expressingthe human TAA NY-ESO-1 and delivering ?-GalCer, namely fdNY-ESO-1/?-GalCer, was analyzedeither in vitro or in vivo, using an HLA-A2 transgenic mouse model (HHK). By using NY-ESO-1-specific TCR-engineered T cells and iNKT hybridoma cells, we observed the efficacy of the fdNY-ESO-1/?-GalCer co-delivery strategy at inducing activation of both the cell subsets. Moreover, invivo administration of fdNY-ESO-1 decorated with ?-GalCer lipid in the absence of adjuvantsstrongly enhances the expansion of NY-ESO-1-specific CD8+ T cells in HHK mice. In conclusion,the filamentous bacteriophage delivering TAA-derived peptides and the ?-GalCer lipid mayrepresent a novel and promising anti-tumor vaccination strateg