Interleukin-28B dampens protease-induced lung inflammation via IL-25 and TSLP inhibition in epithelial cells.

Asthma is a chronic respiratory disease with high heterogeneity in human. Different mouse models have been applied for investigation of pathogenesis and treatment of asthma, which target on different cells, receptors and pathways. Interleukin (IL-) 28B, a member of λ-interferons, have been shown to play a protective role in OVA-induced asthma, which is antigen-specific and adaptive immune system dominant. However, the roles of IL-28B in protease-induced asthma, an adaptive immune system independent asthma, are still unclear. Here, we used plant-derived cysteine protease, papain to induce asthma in mice and found that IL-28B was capable of alleviating papain-induced asthma. Papain challenge lead to activation of epithelial cells and production of alarmin, such as IL-25 and thymic stromal lymphopoietin and IL-28B treatment down-regulated their production. Further mechanism was proved to be that IL-28B inhibited the phosphorylation of Erk in epithelial cells via interaction with their receptors. Our results reveal a protective role of IL-28B via regulation of epithelial cells in protease induced asthma.