Abstract B30: Cross-priming of CD8+ T cells is controlled by dipeptidyl peptidase 3 and thimet oligopeptidase 1 present in necrotic cells.

Abstract

Abstract Cross-priming of CD8+ T cells and generation of effector immune responses is pivotal for tumor immunity, successful anticancer vaccination and therapy. We have discovered a novel molecular mechanism operating in antigen donor cells, which regulates cross-priming of CD8+ T cells during primary sterile necrosis and thereby controls adaptive immune responses. We show that cellular peptidases, dipeptidyl peptidase 3 (DPP-3) and thimet oligopeptidase 1 (TOP-1) present in non-immunogenic necrotic cells eliminate proteasomal degradation products and block antigen cross-presentation. While sterile necrotic tumor cells fail to induce CD8+ T cell responses, their non-immunogenicity can be reversed in vitro and in vivo by inactivation of peptidases, DPP-3 and TOP-1. Thus control of cross-priming and thereby immunogenicity of primary sterile necrosis relies on the proteasome dependent oligopeptide generation and functional status of peptidases in antigen donor cells. Citation Format: Jaba Gamrekelashvili, Tamar Kapanadze, Josef Wissing, Chi Ma, Lothar Jaensch, Firouzeh Korangy, Tim F. Greten. Cross-priming of CD8+ T cells is controlled by dipeptidyl peptidase 3 and thimet oligopeptidase 1 present in necrotic cells. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology: Multidisciplinary Science Driving Basic and Clinical Advances; Dec 2-5, 2012; Miami, FL. Philadelphia (PA): AACR; Cancer Res 2013;73(1 Suppl):Abstract nr B30.