AUTHOR=Song Liqiong , Huang Yuanming , Liu Guoxing , Li Xianping , Xiao Yuchun , Liu Chang , Zhang Yue , Li Jintong , Xu Jianguo , Lu Shan , Ren Zhihong 

TITLE=A Novel Immunobiotics Bacteroides dorei Ameliorates Influenza Virus Infection in Mice

JOURNAL=Frontiers in Immunology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.828887

DOI=10.3389/fimmu.2021.828887

ISSN=1664-3224

ABSTRACT=<sec><title>Objective</title><p>Probiotics can modulate immune responses to resist influenza infection. This study aims to evaluate the anti-viral efficacy of <italic>B. dorei</italic>.</p></sec><sec><title>Methods</title><p>C57BL/6J mice were infected with influenza virus together with treatment of PBS vehicle, <italic>B. dorei</italic>, or oseltamivir respectively. Anti-influenza potency of <italic>B. dorei</italic> and the underlying mechanism were determined by measuring survival rate, lung viral load and pathology, gene expression and production of cytokines and chemokines, and analysis of gut microbiota.</p></sec><sec><title>Results</title><p>Administration of <italic>B. dorei</italic> increased (by 30%) the survival of influenza-infected mice, and improved their weight loss, lung pathology, lung index, and colon length compared to the vehicle control group. <italic>B. dorei</italic> treatment reduced (by 61%) the viral load of lung tissue and increased expression of type 1 interferon more rapidly at day 3 postinfection. At day 7 postinfection, <italic>B.</italic> dorei-treated mice showed lower local (lung) and systemic (serum) levels of interferon and several proinflammatory cytokines or chemokines (IL-1β, IL-6, TNF-α, IL-10, MCP-1 and IP-10) with a efficacy comparable to oseltamivi treatment. <italic>B. dorei</italic> treatment also altered gut microbiota as indicated by increased levels of Bacteroides, Prevotella, and Lactobacillus and decreased levels of Escherichia, Shigella, and Parabacteroides.</p></sec><sec><title>Conclusion</title><p><italic>B. dorei</italic> has anti-influenza effect. Its working mechanisms involve promoting earlier interferon expression and down-regulating both local and systemic inflammatory response. <italic>B. dorei</italic> changes the composition of gut microbiota, which may also contribute to its beneficial effects.</p></sec>