Persistent antigen at vaccination sites induces tumor-specific CD8+ T cell sequestration, dysfunction and deletion

Cancer vaccines have had limited success in eliminating tumors in patients. Here Willem Overwijk and colleagues report that one reason for the failure of peptide-based vaccines may be their formulation. Their research shows that peptides formulated in incomplete Freund's adjuvant sequester CD8+ T cells at the site of injection, leading to T cell dysfunction and eventual apoptosis. A peptide and adjuvant formulation that did not persist long term at the injection site showed superior ability to induce a functional antitumor T cell response.