Microbiota-dependent expansion of testicular IL-17-producing V?6⁺ ?? T cells upon puberty promotes local tissue immune surveillance.

ABSTRACT: ??T cells represent the majority of lymphocytes in several mucosal tissues where they contribute to tissue homoeostasis, microbial defence and wound repair. Here we characterise a population of interleukin (IL) 17-producing ?? (??17) T cells that seed the testis of naive C57BL/6 mice, expand at puberty and persist throughout adulthood. We show that this population is foetal-derived and displays a T-cell receptor (TCR) repertoire highly biased towards V?6-containing rearrangements. These ??17 cells were the major source of IL-17 in the testis, whereas ?? T cells mostly provided interferon (IFN)-? in situ. Importantly, testicular ??17 cell homoeostasis was strongly dependent on the microbiota and Toll-like receptor (TLR4)/IL-1?/IL-23 signalling. We further found that ??17 cells contributed to tissue surveillance in a model of experimental orchitis induced by intra-testicular inoculation of Listeria monocytogenes, as Tcr?^-/- and Il17^-/- infected mice displayed higher bacterial loads than wild-type (WT) controls and died 3 days after infection. Altogether, this study identified a previously unappreciated foetal-derived ??17 cell subset that infiltrates the testis at steady state, expands upon puberty and plays a crucial role in local tissue immune surveillance.

SUBMITTER: Wilharm A 

PROVIDER: S-EPMC7790758 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature