- Conti, Heather R;
- Shen, Fang;
- Nayyar, Namrata;
- Stocum, Eileen;
- Sun, Jianing N;
- Lindemann, Matthew J;
- Ho, Allen W;
- Hai, Justine Hoda;
- Yu, Jeffrey J;
- Jung, Ji Won;
- Filler, Scott G;
- Masso-Welch, Patricia;
- Edgerton, Mira;
- Gaffen, Sarah L
The commensal fungus Candida albicans causes oropharyngeal candidiasis (OPC; thrush) in settings of immunodeficiency. Although disseminated, vaginal, and oral candidiasis are all caused by C. albicans species, host defense against C. albicans varies by anatomical location. T helper 1 (Th1) cells have long been implicated in defense against candidiasis, whereas the role of Th17 cells remains controversial. IL-17 mediates inflammatory pathology in a gastric model of mucosal candidiasis, but is host protective in disseminated disease. Here, we directly compared Th1 and Th17 function in a model of OPC. Th17-deficient (IL-23p19(-/-)) and IL-17R-deficient (IL-17RA(-/-)) mice experienced severe OPC, whereas Th1-deficient (IL-12p35(-/-)) mice showed low fungal burdens and no overt disease. Neutrophil recruitment was impaired in IL-23p19(-/-) and IL-17RA(-/-), but not IL-12(-/-), mice, and TCR-alphabeta cells were more important than TCR-gammadelta cells. Surprisingly, mice deficient in the Th17 cytokine IL-22 were only mildly susceptible to OPC, indicating that IL-17 rather than IL-22 is vital in defense against oral candidiasis. Gene profiling of oral mucosal tissue showed strong induction of Th17 signature genes, including CXC chemokines and beta defensin-3. Saliva from Th17-deficient, but not Th1-deficient, mice exhibited reduced candidacidal activity. Thus, the Th17 lineage, acting largely through IL-17, confers the dominant response to oral candidiasis through neutrophils and antimicrobial factors.