Junior Research Group " Mucosal Immunity "
Institute for Immunology
Hannover Medical School
Carl-Neuberg-Str. 1
30625 Hannover

The distinction of harmless commensal gut microbes from enteric pathogens is a fascinating yet incompletely understood function of the mucosal innate immune system. Microbe-associated molecular patterns such as LPS that are recognized by Toll-like ligands are present on both commensals and pathogens are thus probably insufficient for proper distinction of these microbes. Possibly, addition pathogen-specific molecular patterns, or pathogen-induced tissue damage might induce a switch to appropriate active immune responses.

To test these hypotheses and to identify relevant pathogen properties that allow for immunological distinction from commensals, we use a combination of bacterial and mouse genetics. In particular, we compare a series of progressively attenuated Salmonella enterica strains with defects in one or several virulence systems for their pro-inflammatory capacity in gut-associated lymphoid tissues. Using mouse mutants with defects in innate immunity we determine relevant host signal transduction pathways. This project will reveal detailed information on molecular mechanisms involved in innate immune responses to gut microbes and might facilitate the development of novel intervention strategies against inflammatory bowel disease and the development of efficient oral vaccines against infectious diseases.