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Schlafen-8 (Slfn8) is a member of the Schlafen family of proteins, which harbor helicase domains and are induced by LPS and interferons. It has been reported that the Schlafen family are involved in various cellular functions, including proliferation, differentiation and regulation of virus replication. Slfn8 has been implicated in T-cell differentiation in the thymus. However, the roles of Slfn8 in the immune system remains unclear. In this study, we generated Slfn8 knockout mice (Slfn8−/−) and investigated the immunological role of Slfn8 using the T-cell-mediated autoimmune model experimental autoimmune encephalomyelitis (EAE). We found that the clinical score was reduced in Slfn8−/− mice. IL-6 and IL-17A cytokine production, which are associated with EAE onset and progression, were decreased in the lymph nodes of Slfn8−/− mice. Immune cell populations in Slfn8−/− mice, including macrophages, neutrophils, T cells and B cells, did not reveal significant differences compared with wild-type mice. In vitro activation of Slfn8−/− T cells in response to TCR stimulation also did not reveal significant differences. To confirm the involvement of non-hematopoietic cells, we isolated CD45− CD31+ endothelial cells and CD45−CD31− gp38+ fibroblastic reticular cells by FACS sorting. We showed that the levels of IL-6 and Slfn8 mRNA in CD45− CD31+ endothelial cells were increased after EAE induction. In contrast, the level of IL-6 mRNA after EAE induction was markedly decreased in CD31+ endothelial cells from Slfn8−/− mice. These results indicate that Slfn8 may play a role in EAE by regulating inflammation in endothelial cells.

Monocytes and macrophages comprise a variety of subsets with diverse functions. It is thought that these cells play a crucial role in homeostasis of peripheral organs, key immunological processes and development of various diseases. Among these diseases, fibrosis is a life-threatening disease of unknown aetiology. Its pathogenesis is poorly understood, and there are few effective therapies. The development of fibrosis is associated with activation of monocytes and macrophages. However, the specific subtypes of monocytes and macrophages that are involved in fibrosis have not yet been identified. Here we show that Ceacam1+Msr1+Ly6C-F4/80-Mac1+ monocytes, which we term segregated-nucleus-containing atypical monocytes (SatM), share granulocyte characteristics, are regulated by CCAAT/enhancer binding protein β (C/EBPβ), and are critical for fibrosis. Cebpb deficiency results in a complete lack of SatM. Furthermore, the development of bleomycin-induced fibrosis, but not inflammation, was prevented in chimaeric mice with Cebpb-/- haematopoietic cells. Adoptive transfer of SatM into Cebpb-/- mice resulted in fibrosis. Notably, SatM are derived from Ly6C-FceRI+ granulocyte/macrophage progenitors, and a newly identified SatM progenitor downstream of Ly6C-FceRI+ granulocyte/macrophage progenitors, but not from macrophage/dendritic-cell progenitors. Our results show that SatM are critical for fibrosis and that C/EBPβ licenses differentiation of SatM from their committed progenitor.

The therapeutic activity of checkpoint blockers and toll-like receptor (TLR) agonists, which show some efficacy against malignancies, appears to at least partially result from the secretion of type-I IFNs. Thus, we hypothesized that type-I IFN-inducible transcription factors, such as basic leucine zipper transcription factor ATF-like 2 (Batf2), might play a role in tumor immunity. Here, we investigated the role of Batf2, especially its positive transcriptional activities, and evaluated its antitumor effect. This study shows that Batf2 has an antitumor effect through the up-regulation of IL-12 p40 in tumor-associated macrophages, which eventually induces the activation of CD8+ T cells and their accumulation within the tumor. Batf2 may be an important target in anticancer treatment with immune checkpoint blockers and TLR agonists.

Significance The therapeutic activity of checkpoint blockers and toll-like receptor (TLR) agonists, which show some efficacy against malignancies, appears to at least partially result from the secretion of type-I IFNs. Thus, we hypothesized that type-I IFN-inducible transcription factors, such as basic leucine zipper transcription factor ATF-like 2 ( Batf2 ), might play a role in tumor immunity. Here, we investigated the role of Batf2 , especially its positive transcriptional activities, and evaluated its antitumor effect. This study shows that Batf2 has an antitumor effect through the up-regulation of IL-12 p40 in tumor-associated macrophages, which eventually induces the activation of CD8 + T cells and their accumulation within the tumor. Batf2 may be an important target in anticancer treatment with immune checkpoint blockers and TLR agonists.

An experimental study to generate T-S (Tollmien-Schlichting) waves and oblique waves in a flat plate boundary layer is carried out. This is considered to be the first step towards controlling boundary-layer transition. In order to generate T-S waves and oblique waves, an array of piezoelectrically driven actuator pieces attached to a flat plate surface was used. The actuator pieces were sufficiently thin to keep the boundary layer in the laminar state. In order to generate various oblique waves, ten actuator pieces were aligned in the spanwise direction, each of which could be controlled separately. It is shown that both two-dimensional T-S wave and oblique waves of various angles could be generated using this device. It is also shown that when a flow pattern similar to the Craik-type three-dimensionalization mode was excited, the onset of turbulence took place early and locally at a certain spanwise location.

Experimental study to generate T-S waves and oblique waves in a flat plate boundary layer is carried out. It is regarded as the first step towards controlling the boundary-layer transition. In order to generate T-S waves and oblique waves, an array of piezoelectrically driven actuator pieces attached to the flat plate surface is used. The actuator is thin enough to keep the boundary layer in the laminar-state. In order to generate various oblique waves, the actuator consists of an array of 10 small pieces aligned in the spanwise direction. Each piece can be controlled separately. It is shown that various oblique waves can be successfully generated using this actuator. It is also shown that when the three-dimensionalization mode is induced, the onset of turbulence takes place locally at a certain spanwise location.

Experimental study to generate oblique waves in a flat plate laminar boundary layer is carried out. In order to generate oblique waves, an array of piezoelectrically driven actuator pieces attached to the flat plate surface is used. The actuators are thin enough to keep the boundary layer in the laminar-state. In order to generate oblique waves of various angles, the controlling device consisting of an array of 10 small actuator pieces aligned in the spanwise direction is employed. It is shown that various oblique waves can be generated successfully using this device. However, under certain conditions, the sweep angle of the generated oblique waves was much larger than intended.