Project description:Influenza A(H1N1)pdm virus caused the first human pandemic of the 21st century. Although various probiotic Lactobacillus species have been shown to have anti-microbial effects against pneumonia-inducing pathogens, the prophylactic efficacy and mechanisms behind their protection remain largely unknown. Here, we evaluated the prophylactic efficacy of heat-killed Lactobacillus pentosus b240 against lethal influenza A(H1N1)pdm virus infection in a mouse model. To further define the protective responses induced by b240, we performed virologic, histopathologic, and transcriptomic analyses on the mouse lungs. Although we did not observe an appreciable effect of b240 on virus growth, cytokine production, or histopathology, gene expressional analysis revealed that oral administration of b240 differentially regulates antiviral gene expression in mouse lungs. Our results unveil the possible mechanisms behind the protection mediated by b240 against influenza virus infection and provide new insights into probiotic therapy. Six-week-old female BALB/c mice were used in the study. Oral administration of b240 was initiated in mice at six weeks of age. Mice were orally administered heat-killed Lactobacillus pentosus b240 every day at a dose of 10 mg/mouse in 200 μl of buffered saline for 5 weeks. The control group received saline. To investigate the effects of oral administration of b240 on host immune responses to CA04 virus infection, 9 mice per group were infected with 10 MLD50 of CA04 virus on day 21 post-b240 administration. Three mice per group were euthanized on days 1, 3, and 6 post-infection and their lungs were collected. To investigate the immune responses induced by oral administration of b240 in the lungs of uninfected mice, 15 mice per group were mock-infected with PBS on day 21 post-b240 administration. Three mice per group were euthanized on days 14, 21, 22, 24, and 27 post-b240 administration (-7, 0, 1, 3, and 6 days post-mock infection) and their lungs were collected. These lung tissues were subjected to microarray analysis (three biological replicates per each group).
Project description:Influenza A(H1N1)pdm virus caused the first human pandemic of the 21st century. Although various probiotic Lactobacillus species have been shown to have anti-microbial effects against pneumonia-inducing pathogens, the prophylactic efficacy and mechanisms behind their protection remain largely unknown. Here, we evaluated the prophylactic efficacy of heat-killed Lactobacillus pentosus b240 against lethal influenza A(H1N1)pdm virus infection in a mouse model. To further define the protective responses induced by b240, we performed virologic, histopathologic, and transcriptomic analyses on the mouse lungs. Although we did not observe an appreciable effect of b240 on virus growth, cytokine production, or histopathology, gene expressional analysis revealed that oral administration of b240 differentially regulates antiviral gene expression in mouse lungs. Our results unveil the possible mechanisms behind the protection mediated by b240 against influenza virus infection and provide new insights into probiotic therapy.
