IL-17–producing γδ T cells protect against Clostridium difficile infection
Yee-Shiuan Chen, … , Sing Sing Way, David B. Haslam
Yee-Shiuan Chen, … , Sing Sing Way, David B. Haslam
Published January 28, 2020
Citation Information: J Clin Invest. 2020;130(5):2377-2390. https://doi.org/10.1172/JCI127242.
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Research Article Immunology Infectious disease

IL-17–producing γδ T cells protect against Clostridium difficile infection

Abstract

Colitis caused by Clostridium difficile infection is a growing cause of human morbidity and mortality, especially after antibiotic use in health care settings. The natural immunity of newborn infants and protective host immune mediators against C. difficile infection are not fully understood, with data suggesting that inflammation can be either protective or pathogenic. Here, we show an essential role for IL-17A produced by γδ T cells in host defense against C. difficile infection. Fecal extracts from children with C. difficile infection showed increased IL-17A and T cell receptor γ chain expression, and IL-17 production by intestinal γδ T cells was efficiently induced after infection in mice. C. difficile–induced tissue inflammation and mortality were markedly increased in mice deficient in IL-17A or γδ T cells. Neonatal mice, with naturally expanded RORγt+ γδ T cells poised for IL-17 production were resistant to C. difficile infection, whereas elimination of γδ T cells or IL-17A each efficiently overturned neonatal resistance against infection. These results reveal an expanded role for IL-17–producing γδ T cells in neonatal host defense against infection and provide a mechanistic explanation for the clinically observed resistance of infants to C. difficile colitis.

Authors

Yee-Shiuan Chen, Iuan-Bor Chen, Giang Pham, Tzu-Yu Shao, Hansraj Bangar, Sing Sing Way, David B. Haslam

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Figure 6

C. difficile–responsive IL-17A+ γδ T cells bear a restricted subset of TCR and have a distinctive phenotype.

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C. difficile–responsive IL-17A+ γδ T cells bear a restricted subset of ...
(A) Single-cell suspensions from cecum and colon from day-4–infected mice (4 × 105 CFU) were analyzed by flow cytometry. Gating was done on live CD45+CD3ε+ TCRγδ+ cells. Gray-colored histograms represent the isotype control staining. max, maximum. (B) Distribution of Vγ and Vδ gene usage of IL-17A– and IL-17A+ mLN γδ T cells from day-4–infected mice (4 × 105 CFU). mLN γδ T cells were isolated (see also Supplemental Figure 6) and stimulated in vitro with PMA and ionomycin and labeled by surface cytokine capture. Gene expression was analyzed by RNA-Seq. (C) γδ T cells from mLNs from day-4–infected mice (4 × 105 CFU) were isolated by magnetic beads and cultured for 72 hours with the indicated stimuli (anti-CD3ε, anti-TCRγδ, 10 μg/mL; IL-1β/IL-23, 10 ng/mL). n = 4 per group. Supernatants were then collected analyzed by ELISA. (D) Single-cell suspensions from cecum and colon from day-4–infected mice (4 × 105 CFU) were stimulated with PMA and ionomycin in vitro, followed by intracellular staining and then flow cytometric analysis. Gating was done on live CD45+CD3ε+ TCRγδ+ cells. (E) Heatmap representation of selected genes from RNA-Seq analysis of sorted mLN γδ T cells from day-4–infected mice (4 × 105 CFU). Cells were stimulated in vitro with PMA and ionomycin and labeled by surface cytokine capture, followed by sorting, as in Supplemental Figure 6. I, transcription factors; II, surface receptors; III, effector molecules; IV, cytokine receptors; V, chemokine receptors; VI, TLRs.