The inhibitory receptor TIM-3 limits activation of the cGAS-STING pathway in intra-tumoral dendritic cells by suppressing extracellular DNA uptake

Immunity. 2021 Jun 8;54(6):1154-1167.e7. doi: 10.1016/j.immuni.2021.04.019. Epub 2021 May 11.


Blockade of the inhibitory receptor TIM-3 shows efficacy in cancer immunotherapy clinical trials. TIM-3 inhibits production of the chemokine CXCL9 by XCR1+ classical dendritic cells (cDC1), thereby limiting antitumor immunity in mammary carcinomas. We found that increased CXCL9 expression by splenic cDC1s upon TIM-3 blockade required type I interferons and extracellular DNA. Chemokine expression as well as combinatorial efficacy of TIM-3 blockade and paclitaxel chemotherapy were impaired by deletion of Cgas and Sting. TIM-3 blockade increased uptake of extracellular DNA by cDC1 through an endocytic process that resulted in cytoplasmic localization. DNA uptake and efficacy of TIM-3 blockade required DNA binding by HMGB1, while galectin-9-induced cell surface clustering of TIM-3 was necessary for its suppressive function. Human peripheral blood cDC1s also took up extracellular DNA upon TIM-3 blockade. Thus, TIM-3 regulates endocytosis of extracellular DNA and activation of the cytoplasmic DNA sensing cGAS-STING pathway in cDC1s, with implications for understanding the mechanisms underlying TIM-3 immunotherapy.

Keywords: CD103(+) cDC1; CXCL10; CXCL9; DNA; STING; TIM-3; XCR1(+) cDC1; cGAS; dendritic cells; type I interferon.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Biological Transport / physiology
  • Cell Line
  • Cell Line, Tumor
  • Chemokines / metabolism
  • Cytoplasm / metabolism
  • DNA / metabolism*
  • Dendritic Cells / metabolism*
  • Endocytosis / physiology
  • Female
  • HEK293 Cells
  • Hepatitis A Virus Cellular Receptor 2 / metabolism*
  • Humans
  • Immunotherapy / methods
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Nucleotidyltransferases / metabolism*
  • Signal Transduction / physiology*


  • Chemokines
  • Havcr2 protein, mouse
  • Hepatitis A Virus Cellular Receptor 2
  • Membrane Proteins
  • Sting1 protein, mouse
  • DNA
  • Nucleotidyltransferases
  • cGAS protein, mouse