Our work focuses on research into the interaction between pathogenic and comenal microorganisms and the mucosal immune system in the intestine. We are particularly interested in infections in newborns and children whose mucosal immune systems still have large differences with the immune system of adults. The aim is to identify age-specific mechanisms of pathogen sensitivity and immune defense. On the pathogen side, we investigate various important human pathogenic agents such as .B. salmonella, rotaviruses, listeria, or enteropathogenic E. coli (EPEC). These infectious agents are associated with significant morbidity worldwide and, above all, in children with high mortality. Only a better understanding of the pathogenesis of these infectious diseases and the protective mechanisms of our immune defense scare can lead to better possibilities of prophylaxis and therapy in the long term.