Dietary supplementation with white button mushroom augments the protective immune response to Salmonella vaccine in mice

We previously showed that dietary white button mushrooms (WBM) enhance natural killer cell activity and in vitro WBM promotes maturation and function of dendritic cells (DC). The current study investigated if WBM consumption could enhance pathogen-specific immune response. C57BL/6 mice were fed diets containing 0, 2, or 5% WBM for 4 wk before oral vaccination with live attenuated Salmonella typhimurium. Four wk after immunization, mice were orally infected with S. typhimurium SL1344. Results showed that immunization increased animal survival while WBM alone had no effect; however, among immunized mice, 2% WBM group had a higher survival rate than other groups. We then fed mice 2% WBM to determine the underlying mechanism. We found that Salmonella-specific blood IgG and fecal IgA levels were higher in WBM-fed mice than the control mice. WBM-fed mice also had higher levels of IgG2a and unchanged IgG1 leading to a higher IgG2a/IgG1 ratio, which indicates an enhanced Th1 response. We further found that at 4 w...