Aims: Our study was conducted to evaluate the potent protective effects of oral
administration of probiotic Lactobacillus strains against influenza virus (Flu)
infection in a mouse model.
Method and Results: Lyophilized Lactobacillus rhamnosus GG (LGG) and
Lactobacillus gasseri TMC0356 (TMC0356) were orally administered to BALB ⁄ c
mice for 19 days. The test mice were intranasally infected with Flu A⁄ PR ⁄ 8 ⁄ 34
(H1N1) on day 14, and any changes in clinical symptoms were monitored.
After 6 days of infection, the mice were killed and pulmonary virus titres were
determined. The clinical symptom scores of mice administered oral LGG and
TMC0356 were significantly ameliorated, compared to those of the control
mice (P < 0Æ01). The pulmonary virus titres of the mice fed LGG and
TMC0356 were also significantly decreased compared to those of control mice
(P < 0Æ05).
Conclusions: These results indicate that oral administration of lactobacilli, such
as LGG and TMC0356, might protect a host animal against Flu infection.
Significance and Impact of the Study: These results demonstrate that oral
administration of selected lactobacilli might protect host animals from Flu
infection by interactions with gut immunity.