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The objective of this study was to explore the antioxidant effect of the surface layer proteins (SLPs) and their mechanism. We investigated four SLPs which were extracted from L. casei zhang, L. rhamnosus , L. gasseri and L. acidophilus NCFM respectively using LiCl. The protective effect of SLPs on H 2 O 2 -induced HT-29 cells oxidative injury was investigated. As results, SLPs (100 μg/mL) could significantly mitigate HT-29 cells cytotoxicity, improve the activities of total antioxidant capacity (T-AOC), catalase (CAT) and superoxide dismutase (SOD), decrease the contents of malondialdehyde (MDA) and lactate dehydrogenase (LDH), compared with H 2 O 2 -induced group ( P < 0.05). Furthermore, SLPs were also shown to attenuate the apoptosis rate (10.94–24.03%, P < 0.01), suppress the elevation of intracellular reactive oxygen species (ROS) and calcium levels, restore mitochondrial membrane potential (MMP) and block the activation of apoptosis-related proteins of caspase-3 and caspase-9 ( P < 0.05). Considering all the parameters analyzed, we concluded that Lactobacillus SLPs play an essential role in the antioxidant capacity of HT-29 cells induced by H 2 O 2 , and the mechanism could be attributed to SLPs’ ability to enhance the activity of the intracellular antioxidant enzyme system, reduce ROS accumulation and to inhibit apoptosis by regulating mitochondrial pathway. [ABSTRACT FROM AUTHOR]

Although extensive studies have demonstrated the functional impairment of antigen-specific CD4+ and CD8+ T-cells during chronic hepatitis C virus (HCV) infection, the functional status of global CD4+ and CD8+ T-cells remains unclear. In this report, we recruited 42 long-term (~20 years) treatment-naïve chronic HCV (CHC) patients and 15 healthy donors (HDs) to investigate differences in global CD4+ and CD8+ T-cells function. We show that CD4+ and CD8+ T-cells from CHC patients underwent increased apoptosis after TCR stimulation. Furthermore, IFN-γ, IL-9 and IP-10 were elevated in CHC patients’ plasma and promoted activation-induced T-cells death. Global CD4+ and CD8+ T-cells also showed unique transcriptional profiles in the expression of apoptosis-related genes. We identified BCL2, PMAIP1, and CASP1 in CD4+ T-cells and IER3 and BCL2A1 in CD8+ T-cells from CHC patients as HCV-specific gene signatures. Importantly, the gene expression patterns of CD4+ and CD8+ T-cells from CHC patients differ from those in CD4+ and CD8+ T-cells from human immunodeficiency virus type 1 (HIV-1) or hepatitis B virus (HBV) infected individuals. Our results indicate that chronic HCV infection causes a systemic change in cytokine levels that primes T-cells for activation-induced apoptosis. Furthermore, HCV infection programs unique apoptosis-related gene expression profiles in CD4+ and CD8+ T-cells, leading to their enhanced activation-induced apoptosis. These results provide novel insights to the pathogenesis of chronic HCV infection. [ABSTRACT FROM AUTHOR]