{
  "abstract": "Background Lung cancer is the leading cause of cancer-related deaths worldwide, and non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancer cases. 1Immune checkpoint blockade (ICB) therapy has increased overall survival in a fraction of NSCLC patients, and patients who respond to ICB are usually characterized by a high T cell infiltrate in the tumor.2–4 However, it is important to point out that a fraction of patients with T cell-infiltrated tumors do not respond to ICB.5 6 Understanding why tumor-infiltrating lymphocytes in non-responders fail to respond to ICB can inform the development of more efficacious immunotherapies.Methods To study CD8+ T cell dysfunction in the context of T cell-infiltrated NSCLC, we used a transplantable Kras G12D p53-/- NSCLC cell line engineered to express the model antigen SIINFEKL and injected cells into the lungs or flanks of C57BL/6J mice. Immune cell subsets from tumor-draining lymph nodes (LNs) were profiled using flow cytometry. Interferon-gamma (IFN-γ) levels in LNs were quantified by enzyme-linked immunosorbent assay (ELISA). Regulatory T (Treg) cells in LNs were profiled using paired single-cell RNA and TCR sequencing. Treg suppressive capacity was further interrogated using co-cultures.Results Previous work in the lab demonstrated that abundant levels of IFN-γ in the lung-draining lymph node, or mediastinal lymph node (mLN), induced Th1-like effector Treg cells that suppressed type 1 conventional dendritic cells (DC1s) through an MHCII-dependent interaction. This suppression of DC1s in the mLN resulted in dysfunctional CD8+ T cell priming against lung tumors. In contrast, Tregs present in the flank-draining lymph node, or inguinal lymph node (iLN), exhibited reduced suppressive capacity towards DC1s. Tregs expanded clonally in both tumor-draining mLNs and iLNs but not in naive mLNs and iLNs, suggesting that these Tregs recognize and respond to a tumor-associated antigen. However, whether the Tregs respond to a tumor-specific antigen or a lung antigen upregulated on lung cancer cells remains unclear. To address this, we selected TCR sequences from Tregs that expanded in only the tumor-draining mLN and also both the tumor-draining mLN and iLN. These TCRs will be expressed in Jurkat cells and primary T cells, followed by functional studies paired with immunoproteomics.Conclusions Our work demonstrates that tissue-specific differences shape Treg phenotype and also their specificity. An improved and nuanced understanding of how tolerance is maintained across tissues can inform how tolerance can be overcome with immunotherapy.References Brahmer JR, Govindan R, Anders RA, et al. The Society for Immunotherapy of Cancer consensus statement on immunotherapy for the treatment of non-small cell lung cancer (NSCLC). J Immunother Cancer 2018;6(1):75. doi:10.1186/s40425-018-0382-2Hellmann MD, Paz-Ares L, Bernabe Caro R, et al. Nivolumab plus Ipilimumab in Advanced Non-Small-Cell Lung Cancer. N Engl J Med. 2019;381(21):2020-2031. doi:10.1056/NEJMoa1910231Tumeh PC, Harview CL, Yearley JH, et al. PD-1 blockade induces responses by inhibiting adaptive immune resistance. Nature 2014;515(7528):568-571. doi:10.1038/nature13954Fridman WH, Zitvogel L, Sautès-Fridman C, Kroemer G. The immune contexture in cancer prognosis and treatment. Nat Rev Clin Oncol. 2017;14(12):717-734. doi:10.1038/nrclinonc.2017.101Skoulidis F, Byers LA, Diao L, et al. Co-occurring genomic alterations define major subsets of KRAS-mutant lung adenocarcinoma with distinct biology, immune profiles, and therapeutic vulnerabilities. Cancer Discov. 2015;5(8):860-877. doi:10.1158/2159-8290.CD-14-1236Skoulidis F, Goldberg ME, Greenawalt DM, et al. STK11/LKB1 Mutations and PD-1 Inhibitor Resistance in KRAS-Mutant Lung Adenocarcinoma. Cancer Discov. 2018;8(7):822-835. doi:10.1158/2159-8290.CD-18-0099Ethics Approval All mouse experiments were approved by MIT’s Committee on Animal Care (CAC) – PHS Animal Welfare Assurance # D16-00078 (A3125-01).",
  "authors": [
    {
      "affiliations": [
        "Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA",
        "Massachusetts Institute of Technology, Cambridge, MA, USA"
      ],
      "name": "Molly Carney"
    },
    {
      "affiliations": [
        "Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA",
        "Massachusetts Institute of Technology, Cambridge, MA, USA"
      ],
      "name": "Maria Zagorulya"
    },
    {
      "affiliations": [
        "Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA",
        "Massachusetts Institute of Technology, Cambridge, MA, USA"
      ],
      "name": "Stefani Spranger"
    }
  ],
  "title": "818 Th1-like tregs suppress the CD8+ T cell response to non-small cell lung cancer",
  "uid": "d43c7d6b-4627-58a7-8280-075748358c38"
}