Segmented filamentous bacteria–induced epithelial MHCII regulates cognate CD4+ IELs and epithelial turnover

• DOI: 10.1084/jem.20230194
• Publication Date: 2023-10-30T13:37:00Z
• Authors: Tomáš Brabec; Martin Schwarzer; Katarína Kováčová; Martina Dobešová; Dagmar Schierová; Jiří Březina; Iva Pacáková; Dagmar Šrůtková; Osher Ben-Nun; Yael Goldfarb; Iva Šplíchalová; Michal Kolář; Jakub Abramson; Dominik Filipp; Jan Dobeš
• Keywords: CD4-Positive T-Lymphocytes; Antigen Presentation; Bacteria; Epithelial Cells; Article; Granzymes

Intestinal epithelial cells have the capacity to upregulate MHCII molecules in response certain epithelial-adhesive microbes, such as segmented filamentous bacteria (SFB). However, mechanism regulating expression well impact of MHCII-mediated antigen presentation on T cell responses targeting those microbes remains elusive. Here, we identify cellular network that regulates intestinal epithelium SFB. Since is dispensable for SFB-induced Th17 response, explored other CD4+ cell-based induced by We found SFB drive conversion cognate granzyme+ CD8α+ intraepithelial lymphocytes. These accumulate small space Yet, their accumulation abrogated ablation epithelium. Finally, show this indispensable SFB-driven increase turnover ileum. This study identifies a previously uncharacterized immune SFB, which dependent function.