This represents an important connection between the microbiome and immune system as IL-17 produced by ROR\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\upgamma$$\end{document}γt + Th17s have been shown to contribute to depression- and anxiety-like behaviors17,18. This evidence concerns the gene IL17A and depressive disorder.