Intravenous nanoparticle vaccination generates stem-like TCF1+ neoantigen-specific CD8+ T cells

Personalized cancer vaccines are a promising approach for inducing T cell immunity to tumor neoantigens. Using a self-assembling nanoparticle vaccine that links neoantigen peptides to a Toll-like receptor 7/8 agonist (SNP-7/8a), we show how the route and dose alter the magnitude and quality of neoantigen-specific CD8 + T cells. Intravenous vaccination (SNP-IV) induced a higher proportion of TCF1 + PD-1 + CD8 + T cells as compared to subcutaneous immunization (SNP-SC). Single-cell RNA sequencing showed that SNP-IV induced stem-like genes ( Tcf7 , Slamf6 , Xcl1 ) whereas SNP-SC enriched for effector genes ( Gzmb , Klrg1 , Cx3cr1 ). Stem-like cells generated by SNP-IV proliferated and differentiated into effector cells upon checkpoint blockade, leading to superior antitumor response as compared to SNP-SC in a therapeutic model. The duration of antigen presentation by dendritic cells controlled the magnitude and quality of CD8 + T cells. These data demonstrate how to optimize antitumor immunity by modulating vaccine parameters for specific generation of effector or stem-like CD8 + T cells. Seder and colleagues use a self-assembling nanoparticle vaccine and adjuvant to expand stem-like CD8 + T cells and trigger potent antitumor responses.