Effects of Lactobacillus plantarum and Leuconostoc mesenteroides Probiotics on Human Seasonal and Avian Influenza Viruses

Influenza viruses that cause recurrent seasonal epidemics to humans can be controlled with vaccine and antiviral therapy. However, the medical treatments often exhibit limited efficacy in the elderly or immunosuppressed individuals. In these cases, daily uptake of probiotics may be an option to bring in health benefits against influenza. Here, we demonstrate the effects of probiotics Lactobacillus plantarum (Lp) and Leuconostoc mesenteroides (Lm) against seasonal and avian influenza viruses. As assessed by the plaque size reduction of human H1N1 and avian influenza H7N9 viruses, including green fluorescent protein-tagged H1N1 strain in cells, the selected Lp and Lm strains restrained viral replication in mouse lungs with statistical significance. Against lethal viral challenge, the Lp and Lm strains exhibited their beneficial effects by increasing the mean days and rates of survival of the infected mice. These results suggest that, despite rather narrow ranges of protective efficacy, the dietary supplement of Lactobacillus and Leuconostoc probiotics may promote health benefits against influenza.