MHC class II-restricted antigen presentation is required to prevent dysfunction of cytotoxic T cells by blood-borne myeloids in brain tumors.

Cancer cell 2023 Feb 13

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Cancer immunotherapy critically depends on fitness of cytotoxic and helper T cell responses. Dysfunctional cytotoxic T cell states in the tumor microenvironment (TME) are a major cause of resistance to immunotherapy. Intratumoral myeloid cells, particularly blood-borne myeloids (bbm), are key drivers of T cell dysfunction in the TME. We show here that major histocompatibility complex class II (MHCII)-restricted antigen presentation on bbm is essential to control the growth of brain tumors. Loss of MHCII on bbm drives dysfunctional intratumoral tumor-reactive CD8+ T cell states through increased chromatin accessibility and expression of Tox, a critical regulator of T cell exhaustion. Mechanistically, MHCII-dependent activation of CD4+ T cells restricts myeloid-derived osteopontin that triggers a chronic activation of NFAT2 in tumor-reactive CD8+ T cells. In summary, we provide evidence that MHCII-restricted antigen presentation on bbm is a key mechanism to directly maintain functional cytotoxic T cell states in brain tumors. Copyright © 2022 Elsevier Inc. All rights reserved.

Citation

Michael Kilian, Ron Sheinin, Chin Leng Tan, Mirco Friedrich, Christopher Krämer, Ayelet Kaminitz, Khwab Sanghvi, Katharina Lindner, Yu-Chan Chih, Frederik Cichon, Benjamin Richter, Stefanie Jung, Kristine Jähne, Miriam Ratliff, Robert M Prins, Nima Etminan, Andreas von Deimling, Wolfgang Wick, Asaf Madi, Lukas Bunse, Michael Platten. MHC class II-restricted antigen presentation is required to prevent dysfunction of cytotoxic T cells by blood-borne myeloids in brain tumors. Cancer cell. 2023 Feb 13;41(2):235-251.e9