Lactobacillus paracasei feeding improves immune control of influenza infection in mice.

Nouria Belkacem,James P Di Santo,Ivo Gomperts Boneca,Aurélie Couesnon,Muhamed-Kkeir Taha,Muriel Derrien,Lilia Boucinha,Nadine Cerf-Bensussan,Raphaëlle Bourdet-Sicard,Nicolas Serafini,Richard Wheeler

doi:10.1371/journal.pone.0184976

Abstract

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.

Highlights

Influenza virus is a major source of severe viral respiratory infections in adults, causing annual epidemics that result in important morbidity and mortality
We present evidences that the L. paracasei CNCM I-1518 strain provides a critical benefit in regulating airway tissue integrity and in orchestrating the pulmonary immune defense after experimental infection with influenza virus
To assess the impact of L. paracasei CNCM I-1518 oral administration on resistance toward influenza infection, we first focused on the health status evolution of mice receiving either L. paracasei or control (Phosphate Saline Buffer: PBS) 7 days prior to viral infection

Summary

Introduction

Influenza virus is a major source of severe viral respiratory infections in adults, causing annual epidemics that result in important morbidity and mortality. Major pandemics throughout the 20th century have killed more than 100 million people [1]. The constant threat of the emergence of a novel influenza subtype represents a global danger and necessitates constant. Probiotic and respiratory flu infection 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

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Results

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