LAUSR

Peptide vaccines can be a successful and cost-effective way of generating T-cell responses against defined tumor antigens, especially when combined with immune adjuvants such as poly-IC. However, strong immune adjuvants can induce a collateral increase in numbers of irrelevant, nonspecific T cells, which limits the effectiveness of the peptide vaccines. Here, we report that providing prolonged IL2 signaling in the form of either IL2/ anti-IL2 complexes or pegylated IL2 overcomes the competitive suppressive effect of irrelevant T cells, allowing the preferential expansion of antigen-specific T cells, and increasing the therapeutic effectiveness of the vaccines against established tumors. This vaccination strategy using peptides and sustained IL2 could be taken into the clinic for the treatment of cancer. Citation Format: Takumi Kumai, Hussein Sultan, Yasuaki Harabuchi, Esteban Celis. Sustained persistence of IL-2 signaling enhances the antitumor effect of peptide vaccines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1457.