AUTHOR=Zhang Wei , Wu Qiong , Zhu Yaohong , Yang Guiyan , Yu Jiao , Wang Jiufeng , Ji Haifeng 

TITLE=Probiotic Lactobacillus rhamnosus GG Induces Alterations in Ileal Microbiota With Associated CD3-CD19-T-bet+IFNγ+/- Cell Subset Homeostasis in Pigs Challenged With Salmonella enterica Serovar 4,[5],12:i:-

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.00977

DOI=10.3389/fmicb.2019.00977

ISSN=1664-302X

ABSTRACT=<p><italic>Salmonella enterica</italic> serovar 4,[5],12:i:- (<italic>S.</italic> 4,[5],12:i:-) is an emerging foodborne pathogen causing salmonellosis in humans and animals. Probiotic <italic>Lactobacillus rhamnosus</italic> GG (LGG) is an effective strategy for controlling enteric infections through maintaining gut microbiota homeostasis and regulating the intestinal innate immune response. Here, LGG was orally administrated to newly weaned piglets for 1 week before <italic>S.</italic> 4,[5],12:i:- challenge. <italic>S.</italic> 4,[5],12:i:- challenge led to disturbed gut microbiota, characterized by increased levels of <italic>Psychrobacter, Chryseobacterium indoltheticum</italic>, and uncultured <italic>Corynebacteriaceae</italic> populations, as well as an aberrant correlation network in <italic>Prevotellaceae NK3B31 group</italic>-centric species. The beneficial effect of LGG correlated with attenuating the expansion of <italic>Prevotellaceae NK3B31 group</italic>. <italic>Fusobacterium</italic> only found in the pigs treated with LGG was positively correlated with <italic>Lactobacillus animalis</italic> and <italic>Propionibacterium</italic>. Administration of LGG induced the expansion of CD3<sup>-</sup>CD19<sup>-</sup>T-bet<sup>+</sup>IFNγ<sup>+</sup> and CD3<sup>-</sup>CD19<sup>-</sup>T-bet<sup>+</sup>IFNγ<sup>-</sup> cell subsets in the peripheral blood at 24 h after a challenge of <italic>S.</italic> 4,[5],12:i:-. <italic>S.</italic> 4,[5],12:i:- infection increased the population of intraepithelial CD3<sup>-</sup>CD19<sup>-</sup>T-bet<sup>+</sup>IFNγ<sup>+</sup> and CD3<sup>-</sup>CD19<sup>-</sup>T-bet<sup>+</sup>IFNγ<sup>-</sup> cells in the ileum; however, this increase was attenuated via LGG administration. Correlation analysis revealed that LGG enriched <italic>Flavobacterium frigidarium</italic> and <italic>Facklamia</italic> populations, which were negatively correlated with intraepithelial CD3<sup>-</sup>CD19<sup>-</sup>T-bet<sup>+</sup>IFNγ<sup>+</sup> and CD3<sup>-</sup>CD19<sup>-</sup>T-bet<sup>+</sup>IFNγ<sup>-</sup> cells in the ileum. The present data suggest that probiotic LGG alters gut microbiota with associated CD3<sup>-</sup>CD19<sup>-</sup>T-bet<sup>+</sup>IFNγ<sup>+/-</sup> cell subset homeostasis in pigs challenged with <italic>S. enterica</italic> 4,[5],12:i:-. LGG may be used in potential gut microbiota-targeted therapy regimens to regulate the specific immune cell function and, consequently, control enteric infections.</p>