RegIIIβ fortifies Salmonella Typhimurium invasion of the gut in the early-stage gastrointestinal infection by enhancing flagella-driven locomotion

The bactericidal lectin RegIIIβ is produced by epithelial cells and secreted into the intestinal lumen, where it acts as an innate immune effector by killing the microbiota and enteropathogens. However, it remains to be determined whether RegIIIβ plays roles beyond its bactericidal effects. The present study revealed that RegIIIβ binds to the enteropathogen Salmonella enterica serovar Typhimurium in the gut, thereby increasing the locomotion speed of this bacterium through maintenance of the membrane potential. This led to enhanced invasion by S. Typhimurium into epithelial cells. Finally, RegIIIβ facilitated the gut colonization levels of S. Typhimurium and enteropathy in the early stages of gastrointestinal infection. Our findings provide novel insight into the roles of RegIIIβ in gastrointestinal infection caused by enteropathogens.