This Pillars of Immunology article is a commentary on "Th17 cells and IL-17 receptor signaling are essential for mucosal host defense against oral candidiasis," a pivotal article written by H. R. Conti, F. Shen, N. Nayyar, E. Stocum, J. N. Sun, M. J. Lindemann, A. W. Ho, J. H. Hai, J. J . Yu, J. W. Jung, S. G. Filler, P. Masso-Welch, M. Edgerton, and S. L. Gaffen, and published in The Journal of Experimental Medicine in 2009. https://doi.org/10.1084/jem.20081463.