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IL-28B is a member of the newly discovered type III IFN family and exhibits unique antiviral properties compared with other family members. NK cells play a critical role in defending against viruses; however, little is known about the role of IL-28B in NK cell function. In a mouse model of influenza Avirus (mouse adapted influenza A/PR/8/34 strain) infection, long-term overexpression of IL-28B induced by hepatocyte-specific gene delivery exerted a strong antiviral effect in the presence of NK cells. In IL-28B-overexpressing wild-type mice, the percentages and absolute numbers of NK cells in the spleen, liver, and lung were markedly increased, with higher proliferation and accelerated NK cell maturation based on phenotypes staining with CD11b and CD27 or CD11b and KLRG1. Furthermore, the effect of IL-28B on NK cells was macrophage dependent, as confirmed in an in vitro coculture assay and in in vivo macrophage- or alveolar macrophage-depletion experiments. Transwell studies demonstrated that CFSE-labeled NK cell proliferation was driven, in a dose-dependent manner, by unknown soluble factor(s) secreted by IL-28B-stimulated alveolar macrophages, without requiring direct cell-cell contact. An understanding of the NK cell-promoting features of IL-28B will facilitate future clinical application of this cytokine. [ABSTRACT FROM AUTHOR]

Depression is one of the most common mental disorders in modern society. The disease not only seriously harms people’s quality of life, but also brings a huge burden to families and society because of the high suicide rate and disability rate caused by it. Recent studies have shown that the intestinal flora plays an important role the occurrence and progression of depression and dysfunctional gut-brain communication may be an essential pathological mechanism of depression. The “microbiota-gut-brain” (MGB) axis allows the intestinal flora to participate in the two-way information exchange between the intestine and the brain. Most previous studies mainly focus on exploring the individual characteristics of the intestinal flora in patients with depression and the relationship between the intestinal flora and the occurrence of depression, revealing that maintaining a healthy intestinal flora may be a new idea for the prevention and treatment of depression in the future. This article summarizes recent progress in this research field. We hope that this review can provide insights into the action mechanism of anti-depressive agents from the perspective of the MGB axis, and also provide a reference for the application of probiotics in new depression treatments.

AlthoughNKcells are classified as innate immune cells, recent studies have demonstrated the transformation of NKcells into long-lived memory cells that contribute to secondary immune responses in certain mouse models. However, whether NK cells mount an Agspecific memory response to acute influenza virus infection has not yet been examined. Here, we show that, consistent with previous studies, lung NK cells play an important role in controlling viral proliferation after primary influenza virus infection. However, although lung NK cells display a memory phenotype at the late stage of infection, these cells do not protect mice against secondary influenza virus infection. Interestingly, liver NK cells from influenza virus-infected mice possess a memory phenotype and protect mice against secondary influenza virus infection. Memory-like liver NK cells display a CD49a+DX5- phenotype, and the adoptive transfer of purified liver CD49a+DX5- NK cells into naive mice followed by viral infection results in protective immunity and decreased viral titer. Moreover, we demonstrate that primary inactivated influenza virus induces memory NK cells residing in the liver of Rag1-/- mice. Collectively, these data suggest that liver CD49a+DX5- NK cells remember encountered Ag from influenza virus after primary infection and are more protective upon subsequent infection. [ABSTRACT FROM AUTHOR]