Abstract 2996: CT26 neoantigen presentation and immunogenicity

Abstract

Abstract The foundation of personalized cancer therapy is teaching a patient’s own immune system to directly kill the cancer cells. Vaccination against tumor antigens is one method being explored to generate immune responses against tumors, and may be particularly effective in conjunction with therapies currently in the clinic, such as checkpoint inhibition. Identification of antigens for use in a vaccine is the pinch point of this method, and many algorithms have been developed in an attempt to predict what epitopes will be both presented and immunogenic. Importantly, both public (common to multiple individuals/cancer types) and private (single individual) epitopes may contribute to the development of effective vaccines. Experimental identification of presented and immunogenic epitopes is crucial to building effective anti-cancer vaccines. Using immunopeptidome profiling, we have narrowed a collection of published potential neoantigens to those which were presented by MHC class I in the CT26 mouse colorectal cancer cell line. These peptides were synthesized and used to immunize BALB/c mice. The immunogenicity of the peptide mix was then evaluated by ELIspot to assess IFN-gamma responses in immunized mice. These experiments support a complete workflow for selection of potential cancer neoantigens which experimentally exhibit both MHC presentation and immunogenicity. Citation Format: Seeta Nyayapathy, Richard Jones, Michael Ford, Micah Doty, Julie M. Rumble. CT26 neoantigen presentation and immunogenicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2996.