Ju H., Youn H., Kwon J., Hong W., Song C.
KCAV Co., Ltd., South Korea

Influenza virus infections continue to be a significant public health problem. Generally, the probiotics are considered as immune-modulator and increasing resistance against infectious disease. For improved therapies and preventive measures against influenza, there has been an increased tendency in modern medicine involving the use of probiotics. In particular, oral administration of lactic acid bacteria was proven to be effective in preventing influenza virus infection in mice, but there have been concerns about intact arrival of live bacteria at the intestine after passing through acidic condition of the stomach. Therefore, it has been suggested that intranasal administration of probiotics could be effective on protection against respiratory infection due to direct augment of the respiratory immune system. In this study, we compared the protective efficacy of various live lactic acid bacteria isolated from Korean fermented food (soybean paste [doenjang]) collected from different regions of Korea, and evaluated for their protective efficacy against the influenza virus infection in mice according to the administration route. Moreover, to understand the underlying mechanism behind this clinical protective effect, we performed immunologic assays including examination of IgA levels and cytokine profiles in the lung.

We compared protective efficacy of probiotics from soybean paste against Influenza virus on mice administered by intranasal rout. Among probiotics which showing good result, we compared againt the protective efficacy by oral administration against same virus. Finally, we selected probiotics showing good protective efficacy against Influenza virus on both of administration rout. In addition, to understand the underlying mechanism behind this clinical protective effect, we performed immunologic assays including examination of IgA levels and cytokine profiles(TNF-α, IFN-γ, IL-6, and IL-12) in the lung.

The survival rate of mice receiving intranasal administration of lactic acid bacteria was higher than after oral administration. The interleukin (IL)-12 and IgA levels in lung were significantly increased after intranasal administration. Conversely, the levels of the proinflammatory cytokines, including tumor necrosis factor-alpha and IL-6, were decreased. Interestingly, the protective efficacy of lactic acid bacteria on influenza virus infection was variable among different strains.

In conclusion, intranasal administration of live lactic acid bacteria provided higher protection against influenza virus infection by enhancement of secretory IgA production and down-regulation of pro-inflammatory cytokines in the respiratory immune system. Therefore, selection of effective strains could be critical and individually optimized application regimens of the selected strains are required. Further studies should consider effective strain selection in certain species because each lactic acid bacteria strains could provide a protective efficacy in a strain-dependent manner.

Keywords: Influenza, Mouse, Pedicoccus, Doenjang, Immune, Probiotics

Ju H., et al. (2016). Protective efficacy of Pediococcus lolli against Influenza a virus. Conference Proceedings of IPC2016. Paper presented at the International Scientific Conference on Probiotics and Prebiotics, Budapest (p. 101.). IPC2016

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