摘要：BackgroundThe innate immune system plays a crucial role in the initiation and subsequent direction of adaptive immune responses, as well as in the removal of pathogens that have been targeted by an adaptive immune response.ObjectiveMorus albaL. was reported to have immunostimulatory properties that might protect against infectious diseases. However, this possibility has not yet been explored. The present study investigated the protective and immune-enhancing ability ofM. albaL. against infectious disease and the mechanisms involved.DesignTo investigate the immune-enhancing effects ofM. albaL., we used a bacterial infection model.Results and discussionsThe lifespan of mice infected with a lethal dose ofSalmonella typhimurium(1 × 107colony forming units – CFU) was significantly extended when they were administeredM. albaL. Furthermore,M. albaL. activated macrophages, monocytes, and neutrophils and induced Th1 cytokines (IL-12, IFN-γ, TNF-α) in mice infected with a sublethal dose (1 × 105CFU) ofS. typhimurium.M. albaL. significantly stimulated the uptake of bacteria into peritoneal macrophages as indicated by increased phagocytosis. Peritoneal macrophages derived from C3H/HeJ mice significantly inhibitedM. albaL. induced NO production and TNF-α secretion compared with peritoneal macrophages derived from C3H/HeN mice.ConclusionsThese results suggest that the innate immune activity ofM. albaL. against bacterial infection in mice occurs through activation of the TLR4 signaling pathway.
