薬理と治療

Abstract

Objectives　Lactobacillus plantarum strain SNK12（SNK）, which is isolated from non-salted pickles traditionally consumed in the Kiso area of Nagano prefecture, has potent immunostimulatory effects. In the present study, we verified its protective effects against influenza virus infections by oral administration of the bacteria to mice. Methods　The mice were divided into 3 groups: the control group receiving distilled water, Tamiflu group and SNK group. Each group was orally administered with the corresponding sample from 7 days prior to infection until 14 days after infection. Influenza virus was nasally inoculated, and the viral yields in the respiratory tract lavage（BALF）and the lung were tittered at three days after infection. Neutralizing antibody titers in the sera and BALF samples, and virus-specific IgA levels in the BALF and fecal samples were measured, respectively, at 14 days after infection. Results　The viral yields in the BALF and lung samples were significantly suppressed in SNK group as compared with the control group at 3 days after infection. The neutralizing antibody titers in the BALFs and sera on day 14 after infection were higher in SNK group than those in the control and Tamiflu groups. IgA levels in SNK were also higher in the SNK group than those in the other groups. Conclusions　The activation of innate and/or acquired immune systems by the bacteria might be contributed to the suppression of viral replication and the stimulation of antibody production.