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The treatment and prevention of pathogenic diseases by lactic acid bacteria (LAB) has attracted more and more attention. As a special LAB, Levilactobacillus brevis (L. brevis) has relatively less research on its antibacterial infection in vivo, and its protective effect and mechanism still need to be fully studied. In this study, we selected L. brevis 23017, which can regulate the intestinal immunity of the host animal and resist pathogen infection, to evaluate its protective role and potential molecular mechanisms in the mouse model of S. typhimurium C7731 infection. As expected, we confirmed that L. brevis 23017 reduced the diarrhea rate and increased the daily weight gain and survival rate of the mouse model, and inhibited S. typhimurium colonization in the jejunum and liver. It also reduced the level of oxidative damage and protected the integrity of intestinal tissue by increasing the activity of intestinal antioxidant enzymes (SOD, GSH-Px and T-AOC). From the perspective of intestinal mucosal barrier injury and repair, it was confirmed that L. brevis 23017 could increase the expression levels of intestinal tight junction proteins (ZO-1 and OCLN). Our research results also show that L. brevis 23017 inhibits the inflammatory response and promotes the occurrence of cellular immunity in the body by promoting the increase in IL-10 and inhibiting IL-13 in serum and intestinal tissue. Notably, L. brevis 23017 increased total secretory immunoglobulin A (SIgA) levels in the intestine, which were closely associated with elevated levels of IL-5, IL-13, pIgR, j-chain, and IgAα-chain. In addition, L. brevis 23017 increased the expression of antioxidant proteins Nrf2, NQO1, and HO-1 associated with Nrf2 signaling to inhibit intestinal oxidative damage. This mechanism may be responsible for its protective effect against S. typhimurium-infected intestine. Our study provides new evidence and theoretical support for the analysis of the anti-bacterial infection effect and mechanism of L. brevis, which will contribute to the development of L. brevis and the treatment of pathogenic bacteria intestinal infection. [ABSTRACT FROM AUTHOR]

Background: Tissue-resident CD8+T cells (CD103+CD8+T cells) are the essential effector cell population of anti-tumor immune response in tissue regional immunity. And we have reported that IL-33 can promote the proliferation and effector function of tissue-resident CD103+CD8+T cells. As of now, the immunolocalization and the prognostic values of tissue-resident CD8+T cells in human hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) still remain to be illustrated. Methods: In our present study, we used the tissue microarrays of HCC and ICC, the multicolor immunohistochemistry (mIHC), and imaging analysis to characterize the tissue-resident CD8+T cells in HCC and ICC tissues. The prognostic values and clinical associations were also analyzed. We also studied the biological functions and the cell–cell communication between tumor-infiltrating CD103+CD8+T cells and other cell types in HCC and ICC based on the published single-cell RNA sequencing (scRNA-seq) data. Results: Our work unveiled the expressions of CD8 and CD103 and immunolocalization of tissue-resident CD8+T cells in human HCC and ICC. Elevated CD8+T cells indicated a better overall survival (OS) rate, implying that tumor-infiltrating CD8+T cells in HCC and ICC could serve as an independent prognostic factor. Moreover, the number of CD103+CD8+T cells was increased in HCC and ICC tissues compared with adjacent normal tissues. HCC patients defined as CD8highCD103high had a better OS, and the CD8lowCD103low group tended to have a poorer prognosis in ICC. Evaluation of the CD103+CD8+T-cell ratio in CD8+T cells could also be a prognostic predictor for HCC and ICC patients. A higher ratio of CD103+CD8+T cells over total CD8+T cells in HCC tissues was negatively and significantly associated with the advanced pathological stage. The percentage of higher numbers of CD103+CD8+T cells in ICC tissues was negatively and significantly associated with the advanced pathological stage. In contrast, the higher ratio of CD103+CD8+T cells over total CD8+T cells in ICC tissues was negatively and significantly associated with the advanced pathological stage. In addition, single-cell transcriptomics revealed that CD103+CD8+T cells were enriched in genes associated with T-cell activation, proliferation, cytokine function, and T-cell exhaustion. Conclusion: The CD103+ tumor-specific T cells signified an important prognostic marker with improved OS, and the evaluation of the tissue-resident CD103+CD8+T cells might be helpful in assessing the on-treatment response of liver cancer. [ABSTRACT FROM AUTHOR]

Exhausted CD8 + T cells represent a distinct cellular lineage that emerges during both chronic infections and cancers. Recent studies have shown that persistent antigen exposure can drive the differentiation of precursor exhausted CD8 + T cells, termed T pex cells, which are characterized as TCF-1 + PD-1 + CD8 + T cells. Elevated T pex cell frequencies in the tumor microenvironment (TME) are associated with improved overall survival (OS) in cancer patients and heightened responsiveness to anti-PD-1 therapy. In our present study, we utilized multi-color immunohistochemistry (mIHC) to determine the localization and clinical implications of tumor-infiltrating T pex cells within the TME of human colorectal cancer (CRC) tissues. We also conducted a multi-omics integrative analysis using single-cell RNA sequencing (scRNA-seq) data derived from both the murine MC38 tumor model and human CRC tissues. This analysis helped delineate the transcriptional and functional attributes of T pex cells within the CRC TME. Furthermore, we employed spatial transcriptome sequencing data from CRC patients to investigate the interactions between T pex cells and other immune cell subsets within the TME. In conclusion, our study not only established a method for T pex cell detection using mIHC technology but also confirmed that assessing T pex cells within the CRC TME could be indicative of patients' survival. We further uncovered the transcriptional and functional characteristics of T pex cells in the TME and ascertained their pivotal role in the efficacy of immunotherapy against CRC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Huang, Ge, Fang, Wu, Jiang, Lang, Chen, Xiao, Xu, Liu, Chen, Zheng and Jiang.)

Background: Immune-based therapies are commonly employed to combat hepatocellular carcinoma (HCC). However, the presence of immune-regulating elements, especially regulatory T cells (Tregs), can dramatically impact the treatment efficacy. A deeper examination of the immune-regulation mechanisms linked to these inhibitory factors and their impact on HCC patient outcomes is warranted., Methods: We employed multicolor fluorescence immunohistochemistry (mIHC) to stain Foxp3, cytokeratin, and nuclei on an HCC tissue microarray (TMA). Leveraging liver cancer transcriptome data from TCGA, we built a prognostic model focused on Treg-associated gene sets and represented it with a nomogram. We then sourced liver cancer single-cell RNA sequencing data (GSE140228) from the GEO database, selectively focusing on Treg subsets, and conducted further analyses, including cell-to-cell communication and pseudo-time trajectory examination., Results: Our mIHC results revealed a more substantial presence of Foxp3 + Tregs in HCC samples than in adjacent normal tissue samples ( P < .001). An increased presence of Foxp3 + Tregs in HCC samples correlated with unfavorable patient outcomes ( HR = 1.722, 95% CI :1.023-2.899, P = .041). The multi-factorial prognosis model we built from TCGA liver cancer data highlighted Tregs as a standalone risk determinant for predicting outcomes ( HR = 3.84, 95% CI: 2.52-5.83, P < .001). Re-analyzing the scRNA-seq dataset (GSE140228) showcased distinctive gene expression patterns in Tregs from varying tissues. Interactions between Tregs and other CD4 + T cell types were predominantly governed by the CXCL13/CXCR3 signaling pathway. Communication pathways between Tregs and macrophages primarily involved MIF-CD74/CXCR4, LGALS9/CD45, and PTPRC/MRC1. Additionally, macrophages could influence Tregs via HLA-class II and CD4 interactions., Conclusion: An elevated presence of Tregs in HCC samples correlated with negative patient outcomes. Elucidating the interplay between Tregs and other immune cells in HCC could provide insights into the modulatory role of Tregs within HCC tissues., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

TMP269, a small molecular inhibitor of IIa histone deacetylase, plays a vital role in cancer therapeutic. However, the effect of TMP269 on the regulation of viral replication has not been studied. In the present study, we found that TMP269 treatment significantly inhibited RABV replication at concentrations without significant cytotoxicity in a dose-dependent manner. In addition, TMP269 can reduce the viral titers and protein levels of RABV at an early stage in the viral life cycle. RNA sequencing data revealed that immune-related pathways and autophagy-related genes were significantly downregulated after RABV infection treated with TMP269. Further exploration shows that autophagy enhances RABV replication in HEK-293T cells, while TMP269 can inhibit autophagy to decrease RABV replication. Together, these results provide a novel treatment strategy for rabies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Yin, Wang, Ren, Liang, Ge, Sun, Yin and Wang.)

It is well-known that CD226 serves as a critical activating receptor on various immune cells, such as lymphocytes and monocytes, and it is suggested to promote anti-tumor immunity in the tumor microenvironment (TME). Herein, we showed a crucial regulatory role of CD226 in CD8 + T cell-mediated anti-tumor response in TME of human gastric cancer (GC). Specifically, the increased CD226 expression in cancer tissues was significantly associated with better clinical outcomes in GC patients. Moreover, the increased infiltrating CD226 + CD8 + T cells and the increased ratio of infiltrating CD226 + CD8 + T cells in CD8 + T subpopulation within cancer tissues could also be valuable prognostic predictors for GC patients. Mechanically, the assay for transposase-accessible chromatin using sequencing (ATAC-seq) analysis revealed that the chromatin accessibility of CD226 in CD4 + and CD8 + TILs was significantly higher than that in CD8 + T cells in normal tissues. Further analysis showed that CD8 + TILs highly expressed immune checkpoint molecules, such as TIGIT , LAG3 , and HAVCR2 , which means CD8 + TILs are more exhausted. In addition, our multi-color immunohistochemical staining (mIHC) revealed that GC patients with higher frequency of IFN-γ + CD226 + CD8 + TILs showed poorer prognosis. Combined with the single-cell transcriptome sequencing (scRNA-seq) data analysis, we found that the expressions of IFN-γ and TIGIT in CD8 + TILs were significantly and positively correlated. The expression of TIGIT in IFN-γ + CD226 + CD8 + TILs was higher, while that in IFN-γ - CD226 + CD8 + TILs was significantly lower. The correlation analysis showed that the expression of CD226 was positively correlated with the score of effector T cells but negatively correlated with that of immunosuppressive factors, such as Tregs and tumor-associated macrophages (TAMs). Collectively, we showed that the frequency of CD226 + CD8 + TILs was an excellent prognostic predictor for GC patients. Our findings provided insights into the interaction pattern between co-stimulatory receptor CD226 and tumor cells as well as the infiltrating immune cells in the TME in GC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Huang, Huang, Ge, Yang, Chen, Xu, Wu, Zheng, Chen, Zhang and Jiang.)