TLR2 in ?d T cells is required for metabolic support of IL-17A ocular mucosal immune response to a commensal bacterium [ATAC-seq]

The ocular surface is colonized by commensal microbiota, which tune the local mucosal immune response. However, the mechanisms underlying the induction of an IL-17 response by ?d T cells in response to ocular commensal bacteria, particularly Corynebacterium mastitidis (C. mast), have not been fully investigated. Here, we demonstrated that intrinsic TLR2 activation in ?d T cells by commensal microbiota is required for their IL-17A production and fatty acid oxidation. We also identified I?B?, a transcription factor whose expression is upregulated by TLR2 signaling, as a key regulator to enhance the expression of genes responsible for IL-17A production and FAO program. This study highlights the role of TLR2-mediated transcriptional regulation in targeting effector cytokines and metabolic programs to support IL-17A responses to commensal bacteria. Overall design: WT C57BL/6J mice were purchased from Jackson Laboratory. TLR2-/-, TCRß-/-, and CD45.1 C57BL/6J mice originally from Jackson were bred at NIH. V?6 transgenic mice were generously provided by Paul E. Love; TLR2-/-V?6 transgenic mice, and TLR2-/- TCRß-/- mice were crossed and bred at NIH. For most in vivo and in vitro animal studies, male and female mice aged 6-10 weeks were used. All mice were housed under NIH SPF conditions. All mice received tear wash and were confirmed with no microbiome on the ocular surface before the experiment. All mouse studies were performed in full compliance with IACUC-approved protocols (NEI-690) and institutional guidelines. C. mast was initially isolated from conjunctival homogenates that were plated on TSA + 5% blood agar plates kept at 37? in anaerobic conditions for 7 days. After original isolation, C. mast was propagated using TSA with 5% blood agar plates at 37? in an aerobic chamber. Further, C. mast was grown in blood heart infusion broth with 1% Tween 80 aerobically with shaking at 37?.