My research innovatively integrates gnotobiotic murine models, immunology, microbiology, and characterization of the microbiota with the ultimate aim of identifying specific commensal bacteria with immunomodulatory potential and subsequent characterization of their biologic effects. We have recently developed an inventive approach for identifying with high specificity organisms within the microbiota that are causally related to the phenotype of interest. Using this approach of microbe–phenotype triangulation, we identified Clostridium immunis, a new bacterial species that protects against colitis in murine models, and two bacterial species that induce host expression of a critical antimicrobial peptide. We are now investigating the molecular mechanisms—from both the bacterial and host perspectives—that underlie these host–commensal relationships. Furthermore, we are extending our discovery platform to human samples and additional disease processes to identify more causal microbes.
