Molecular Mechanisms of , LGG Probiotic Function.

To advance probiotic research, a comprehensive understanding of bacterial interactions with human physiology at the molecular and cellular levels is fundamental. LGG is a bacterial strain that has long been recognized for its beneficial effects on human health. Probiotic effector molecules derived from LGG, including secreted proteins, surface-anchored proteins, polysaccharides, and lipoteichoic acids, which interact with host physiological processes have been identified. In vitro and animal studies have revealed that specific LGG effector molecules stimulate epithelial cell survival, preserve intestinal barrier integrity, reduce oxidative stress, mitigate excessive mucosal inflammation, enhance IgA secretion, and provide long-term protection through epigenetic imprinting. Pili on the cell surface of LGG promote adhesion to the intestinal mucosa and ensure close contact to host cells. Extracellular vesicles produced by LGG recapitulate many of these effects through their cargo of effector molecules. Collectively, the effector molecules of LGG exert a significant influence on both the gut mucosa and immune system, which promotes intestinal homeostasis and immune tolerance.