Lactobacillus paracasei feeding improves immune control of influenza infection in mice

PLoS One. 2017 Sep 20;12(9):e0184976. doi: 10.1371/journal.pone.0184976. eCollection 2017.


Respiratory tract infections such as flu cause severe morbidity and mortality and are among the leading causes of death in children and adults worldwide. Commensal microbiota is critical for orchestrating tissue homeostasis and immunity in the intestine. Probiotics represent an interesting source of immune modulators and several clinical studies have addressed the potential beneficial effects of probiotics against respiratory infections. Therefore, we have investigated the mechanisms of protection conferred by L. paracasei CNCM I-1518 strain in a mouse model of influenza infection. Notably, local myeloid cells accumulation is generated in the lungs after seven days feeding with L. paracasei prior to viral infection. L. paracasei-fed mice showed reduced susceptibility to the influenza infection, associated with less accumulation of inflammatory cells in the lungs, faster viral clearance and general health improvement. Interestingly, Allobaculum was significantly increased in L. paracasei-fed mice 7 days after influenza infection, even if the gut microbiota composition was not altered overall. L. paracasei-purified peptidoglycan partially recapitulated the protective phenotype observed with the entire bacteria. Collectively, our results demonstrate that oral consumption of L. paracasei CNCM I-1518 modulates lung immunity was associated with an improved control of influenza infection. These results further extend the beneficial role for certain lactobacilli to alleviate the burden of respiratory tract infections.

MeSH terms

  • Animals
  • Colony Count, Microbial
  • Female
  • Immunity, Cellular / immunology*
  • Lacticaseibacillus paracasei / physiology*
  • Mice
  • Mice, Inbred BALB C
  • Orthomyxoviridae / immunology*
  • Orthomyxoviridae Infections / immunology*
  • Orthomyxoviridae Infections / microbiology
  • Orthomyxoviridae Infections / prevention & control
  • Probiotics / administration & dosage*
  • Respiratory Tract Infections / immunology*
  • Respiratory Tract Infections / microbiology
  • Respiratory Tract Infections / prevention & control

Grants and funding

The study was supported by the following grants: CI IMMUNOBIOTIC 1307014/00 IRT BAP301, Danone 30000221 as well as by the Institut Pasteur. In addition to funding, Danone Nutricia Research and Bioaster provided coordination and management. In addition, Danone Nutricia Research made available Lactobacilli strains and performed Microbiota analysis. The funders had no role in study design, decision to publish, or preparation of the manuscript. MD and RBS are employed by Danone Nutricia Research. Danone Nutricia Research provided support in the form of salaries for authors MD and RBS, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.