Peptidases released by necrotic cells control CD8+ T cell cross-priming
Jaba Gamrekelashvili, … , Firouzeh Korangy, Tim F. Greten
Jaba Gamrekelashvili, … , Firouzeh Korangy, Tim F. Greten
Published October 8, 2013
Citation Information: J Clin Invest. 2013;123(11):4755-4768. https://doi.org/10.1172/JCI65698.
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Research Article Immunology

Peptidases released by necrotic cells control CD8+ T cell cross-priming

Abstract

Cross-priming of CD8+ T cells and generation of effector immune responses is pivotal for tumor immunity as well as for successful anticancer vaccination and therapy. Dead and dying cells produce signals that can influence Ag processing and presentation; however, there is conflicting evidence regarding the immunogenicity of necrotic cell death. We used a mouse model of sterile necrosis, in which mice were injected with sterile primary necrotic cells, to investigate a role of these cells in priming of CD8+ T cells. We discovered a molecular mechanism operating in Ag donor cells that regulates cross-priming of CD8+ T cells during primary sterile necrosis and thereby controls adaptive immune responses. We found that the cellular peptidases dipeptidyl peptidase 3 (DPP-3) and thimet oligopeptidase 1 (TOP-1), both of which are present in nonimmunogenic necrotic cells, eliminated proteasomal degradation products and blocked Ag cross-presentation. While sterile necrotic tumor cells failed to induce CD8+ T cell responses, their nonimmunogenicity could be reversed in vitro and in vivo by inactivation of DPP-3 and TOP-1. These results indicate that control of cross-priming and thereby immunogenicity of primary sterile necrosis relies on proteasome-dependent oligopeptide generation and functional status of peptidases in Ag donor cells.

Authors

Jaba Gamrekelashvili, Tamar Kapanadze, Miaojun Han, Josef Wissing, Chi Ma, Lothar Jaensch, Michael P. Manns, Todd Armstrong, Elizabeth Jaffee, Ayla O. White, Deborah E. Citrin, Firouzeh Korangy, Tim F. Greten

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Figure 2

Primary FT necrotic cells abort cross-priming of CD8+ T cells.

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Primary FT necrotic cells abort cross-priming of CD8+ T cells. (A) B78...
(A) B78OVA-FTheat cells were mixed with B78-FT cells at a 1:8 ratio and injected into mice on days 0 and 2, so that each mouse was vaccinated with a total of 2 × 106 B78OVA cells. Ag-specific immune responses were analyzed on day 7. Data are mean ± SEM of 2 pooled experiments (n = 3 per group). (B) SF of 2.5 × 105 B78OVA-FTheat cells was cultured in vitro with CFSE-labeled OT-I splenocytes, and titrated amount of SF from B78-FT was added. Proliferation of CD8+ T cells was analyzed after 48 hours. Data are representative of at least 3 independent experiments. Inset shows proliferation of OVA-specific CFSE-labeled CD8+ T cells cultured with B78OVA-FTheat or B78OVA-FTheat +B78-FT cells. (C and D) SF from B78-FT cells was trypsin digested and added at different dilutions to CFSE-labeled OT-I cells in the presence of 20 μg/ml OVA. Proliferation (C) and IFN-γ expression (D) of CD8+ T cells were analyzed 48 hours later. Data are representative of at least 3 experiments. (E and F) Trypsin-digested SF from CT26-FT or B78-FT cells were added to CFSE-labeled OT-I splenocytes in the presence of 20 μg/ml OVA, and Ag-specific proliferation (E) and IFN-γ expression (F) was tested. Data are representative of at least 3 experiments. *P < 0.05, **P < 0.01, ***P < 0.001, Student’s t test (A and C–F) or 1-way ANOVA with Dunnett’s multiple-comparison test (B).