Chlorine dioxide (ClO2) is used as a disinfectant in food and environmental sanitation. However, information regarding its efficacy against enterohemorrhagic Escherichia coli (EHEC) under organic load conditions remains limited. This study evaluated the bactericidal activity of aqueous ClO2 against clinically important EHEC serogroups and compared its efficacy with that of sodium hypochlorite (NaClO). Additionally, other bacterial strains, including enteropathogenic E. coli (EPEC), Escherichia albertii, and E. coli type strains, were also examined. Under organic load conditions, treatment with 100 ppm NaClO resulted in only minor reductions (< 1 log(10) CFU/mL) within 60 s for all strains tested. In contrast, 10 ppm ClO2 reduced the E. coli type strain and E. albertii by > 3 log(10) CFU/mL, while 100 ppm ClO2 reduced all tested strains to below the detection limit (> 6 log(10) CFU/mL reduction). EHEC and EPEC strains showed lower susceptibility to 10 ppm ClO2 (0.2-1.3 log(10) CFU/mL reduction) but were reduced to below the detection limit by 100 ppm ClO2. Time-course assay further demonstrated that 100 and 30 ppm ClO2 inactivated > 6 log(10) CFU/mL of EHEC within 15 and 30 s, respectively, whereas NaClO showed only limited bactericidal activity over the same period. These results demonstrate that ClO2 provides substantially greater and more rapid bactericidal activity than NaClO against EHEC in the presence of organic matter. The findings provide quantitative evidence of the concentration- and time-dependent bactericidal efficacy of ClO2 and provide fundamental information for future studies evaluating its potential application in food hygiene and environmental sanitation.
ABSTRACT Sepsis is a life‐threatening condition characterized by dysregulated systemic inflammation and high mortality rates. Mesenchymal stem/stromal cells (MSCs) have emerged as promising immunomodulatory agents; however, genetic engineering strategies can enhance their therapeutic efficacy. This study evaluated the immunomodulatory and protective effects of MSCs genetically engineered to express leukemia inhibitory factor (MSC‐LIF) in vitro and in a mouse model of lipopolysaccharide (LPS)‐induced endotoxemia. In vitro, peritoneal macrophages stimulated with LPS + IFN‐γ were co‐cultured with MSC‐LIF or wild‐type MSCs (MSC‐WT). MSC‐LIF significantly reduced the production of TNF‐α, IL‐12, and nitric oxide compared with stimulated controls and demonstrated enhanced inhibition of IL‐12 and nitrite levels relative to MSC‐WT. Although IL‐6 levels increased in co‐cultures, MSC‐LIF promoted a regulatory cytokine profile characterized by modulation of pro‐inflammatory mediators. In vivo, C57BL/6 mice subjected to lethal endotoxemia with LPS were treated with MSC‐LIF, MSC‐WT, dexamethasone, or vehicle. MSC‐LIF significantly improved survival in a dose‐dependent manner, achieving 100% survival at the highest dose (1 × 10 6 cells), outperforming MSC‐WT. Serum cytokine analysis revealed that MSC‐LIF markedly reduced TNF‐α, IL‐6, IL‐1β, and IL‐12 levels while significantly increasing IL‐10 production, indicating enhanced systemic immunoregulation. Collectively, these findings demonstrate that LIF expression potentiates the immunomodulatory and protective effects of MSCs in experimental endotoxemia. MSC‐LIF therapy promotes a balanced inflammatory response and significantly improves survival, supporting its potential as a novel therapeutic strategy for severe systemic inflammatory conditions such as sepsis.
ABSTRACT Azole resistance in Aspergillus fumigatus is increasing globally, necessitating novel combination strategies to restore the efficacy of first‐line antifungals such as voriconazole (VCZ). Andrographolide (ADR), a natural diterpene lactone, has shown limited direct antifungal activity but exhibits synergistic effects with amphotericin B and immunomodulatory properties. However, its potential as an adjunct to VCZ against Aspergillus species remains unexplored. The in vitro antifungal activity of ADR combined with VCZ was evaluated against A. fumigatus , Aspergillus flavus , and Aspergillus niger using the broth microdilution checkerboard method. Biofilm formation was assessed by Congo red agar, XTT reduction, and crystal violet staining. Cytotoxicity was measured via CCK‐8 assay on A549 lung epithelial cells. Transcriptomic analysis (RNA‐seq) and qPCR were performed to uncover the synergistic mechanism. The ADR‐VCZ combination exhibited synergy against A. fumigatus (FICI = 0.5) and additive effects against A. flavus (FICI = 0.75) and A. niger (FICI = 1.0). ADR alone showed minimal antifungal activity (MIC = 400 µg/mL). However, when combined with VCZ, it reduced the MIC of VCZ from 0.5 to 0.125 µg/mL. The combination significantly inhibited A. fumigatus biofilm formation without detectable cytotoxicity to A549 cells. Transcriptomic analysis revealed that the VCZ versus Control comparison and the ADR + VCZ versus VCZ comparison shared one common downregulated gene ( AFUA_4G03760 ) and were co‐enriched in three GO terms related to serine family amino acid catabolic processes. Four serine family metabolism‐related genes ( AFUA_4G03760 , AFUA_1G10780 , AFUA_2G07810 , and AFUA_3G09320 ) were significantly downregulated, as confirmed by qPCR. ADR may act as an effective booster of VCZ against A. fumigatus , with transcriptomic data pointing to downregulation of genes involved in serine family metabolism and biofilm inhibition. This study provides a preliminary metabolic clue for combating aspergillosis.
Tumor-associated monocytes and macrophages are abundant in the tumor microenvironment (TME) and can influence the therapeutic accessibility of antibody drugs. However, the impact of macrophage-mediated antibody sequestration on the therapeutic efficacy of anti-epidermal growth factor receptor (EGFR) therapy remains unclear. This study aimed to assess whether monocytes and macrophages attenuate anti-EGFR therapeutic efficacy by sequestering antibodies. We established a transwell-based co-culture platform using human THP-1 monocytes or macrophages and EGFR-positive DiFi colorectal cancer cells to evaluate macrophage-associated antibody sequestration. In vivo xenograft assays, flow cytometric uptake analyses and inhibitor-based functional studies were performed using the anti-EGFR monoclonal antibodies cetuximab and panitumumab. Xenograft models co-implanted with THP-1 cells demonstrated attenuated responses to anti-EGFR antibodies compared to tumor-only models. Monocytes and macrophages significantly reduced the growth-inhibitory effects of cetuximab and panitumumab in co-culture. Antibody uptake was increased in THP-1 cells and THP-1-derived macrophages. Fc receptor blockade and uptake-associated inhibitors partially suppressed antibody uptake and restored antibody-mediated anti-tumor activity, suggesting the involvement of Fc gamma R-dependent and Fc gamma R-independent pathways. Monocyte- and macrophage-mediated antibody sequestration attenuates anti-EGFR therapeutic efficacy by reducing antibody accessibility to tumor cells. The established co-culture platform provides a useful bioanalytical assay system to screen and evaluate antibody accessibility and macrophage-associated sequestration during the preclinical development of antibody therapeutics.
ABSTRACT Chlorine dioxide (ClO 2 ) is used as a disinfectant in food and environmental sanitation. However, information regarding its efficacy against enterohemorrhagic Escherichia coli (EHEC) under organic load conditions remains limited. This study evaluated the bactericidal activity of aqueous ClO 2 against clinically important EHEC serogroups and compared its efficacy with that of sodium hypochlorite (NaClO). Additionally, other bacterial strains, including enteropathogenic E. coli (EPEC), Escherichia albertii , and E. coli type strains, were also examined. Under organic load conditions, treatment with 100 ppm NaClO resulted in only minor reductions (< 1 log 10 CFU/mL) within 60 s for all strains tested. In contrast, 10 ppm ClO 2 reduced the E. coli type strain and E. albertii by > 3 log 10 CFU/mL, while 100 ppm ClO 2 reduced all tested strains to below the detection limit (> 6 log 10 CFU/mL reduction). EHEC and EPEC strains showed lower susceptibility to 10 ppm ClO 2 (0.2–1.3 log 10 CFU/mL reduction) but were reduced to below the detection limit by 100 ppm ClO 2 . Time‐course assay further demonstrated that 100 and 30 ppm ClO 2 inactivated > 6 log 10 CFU/mL of EHEC within 15 and 30 s, respectively, whereas NaClO showed only limited bactericidal activity over the same period. These results demonstrate that ClO 2 provides substantially greater and more rapid bactericidal activity than NaClO against EHEC in the presence of organic matter. The findings provide quantitative evidence of the concentration‐ and time‐dependent bactericidal efficacy of ClO 2 and provide fundamental information for future studies evaluating its potential application in food hygiene and environmental sanitation.
