T Cell Intrinsic USP15 Deficiency Promotes Excessive IFN-γ Production and an Immunosuppressive Tumor Microenvironment in MCA-Induced Fibrosarcoma.

USP15 is a deubiquitinase that negatively regulates activation of naive CD4(+) T cells and generation of IFN-γ-producing T helper 1 (Th1) cells. USP15 deficiency in mice promotes antitumor T cell responses in a transplantable cancer model; however, it has remained unclear how deregulated T cell activation impacts primary tumor development during the prolonged interplay between tumors and the immune system. Here, we find that the USP15-deficient mice are hypersensitive to methylcholantrene (MCA)-induced fibrosarcomas. Excessive IFN-γ production in USP15-deficient mice promotes expression of the immunosuppressive molecule PD-L1 and the chemokine CXCL12, causing accumulation of T-bet(+) regulatory T cells and CD11b(+)Gr-1(+) myeloid-derived suppressor cells at tumor site. Mixed bone marrow adoptive transfer studies further reveals a T cell-intrinsic role for USP15 in regulating IFN-γ production and tumor development. These findings suggest that T cell intrinsic USP15 deficiency causes excessive production of IFN-γ, which promotes an immunosuppressive tumor microenvironment during MCA-induced primary tumorigenesis. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Citation

Qiang Zou, Jin Jin, Yichuan Xiao, Xiaofei Zhou, Hongbo Hu, Xuhong Cheng, Nasser Kazimi, Stephen E Ullrich, Shao-Cong Sun. T Cell Intrinsic USP15 Deficiency Promotes Excessive IFN-γ Production and an Immunosuppressive Tumor Microenvironment in MCA-Induced Fibrosarcoma. Cell reports. 2015 Dec 22;13(11):2470-9

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PMID: 26686633

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