Meningeal gd T cells regulate anxiety like behaviors via Il17a signaling on Neurons

By characterizing the meningeal compartment of naive mice, here we explored a unique population of tissue-resident gd T cells, which we found to be the major source of IL-17A in the steady state meninges. gd T cells rapidly harbor meninges at perinatal stages and actively make IL-17A. Their IL-17A production was TCR-dependent but it occurred independent of commensal microbiota. The absence of meningeal gd T cells was related with risk-taking behavior in mice, which was dependent on the IL-17A signaling directly in the prefrontal cortex neurons. Our results demonstrate that tissue-resident meningeal gd T cell-derived IL-17A may represent an evolutionary bridge between anti-pathogen response and avoidance behavioral traits in vertebrates. Overall design: Each sample for meningeal gd T cells (Adults; n = 1 and Pups; n = 1) was obtained by pooling 15 animals. For splenic gd T cells (Adults; n = 1 and Pups; n = 1), it was pooled 5 mice.