ILC3s control airway inflammation by limiting T cell responses to allergens and microbes.

From PubMed via Jisc Publications RouterHistory: received 2021-06-02, revised 2021-09-28, accepted 2021-11-02Publication status: ppublishFunder: NIAID NIH HHS; Grant(s): R01 AI162936, P01 AI106697, R01 AI145989, R01 AI123368, R01 AI143842, U01 AI095608Funder: Wellcome TrustFunder: NCI NIH HHS; Grant(s): R21 CA249274Group 3 innate lymphoid cells (ILC3s) critically regulate host-microbe interactions in the gastrointestinal tract, but their role in the airway remains poorly understood. Here, we demonstrate that lymphoid-tissue-inducer (LTi)-like ILC3s are enriched in the lung-draining lymph nodes of healthy mice and humans. These ILC3s abundantly express major histocompatibility complex class II (MHC class II) and functionally restrict the expansion of allergen-specific CD4 T cells upon experimental airway challenge. In a mouse model of house-dust-mite-induced allergic airway inflammation, MHC class II ILC3s limit T helper type 2 (Th2) cell responses, eosinophilia, and airway hyperresponsiveness. Furthermore, MHC class II ILC3s limit a concomitant Th17 cell response and airway neutrophilia. This exacerbated Th17 cell response requires exposure of the lung to microbial stimuli, which can be found associated with house dust mites. These findings demonstrate a critical role for antigen-presenting ILC3s in orchestrating immune tolerance in the airway by restricting pro-inflammatory T cell responses to both allergens and microbes. [Abstract copyright: Crown Copyright © 2021. Published by Elsevier Inc. All rights reserved.