Biosciences Research Seminar - Immune cell mechanisms that regulate fungal commensalism vs disease

Skin and mucosal surfaces of animals and man are covered with myriads of microbes that create complex ecosystems with their host. The constant exposure of the host to microbes shapes the immune reactivity of the host locally and at distant sites, and it even influences seemingly unrelated processes ranging from digestion to behavior. Perturbations that disrupt the equilibrium of the microbial ecosystem may lead to the overgrowth of species with pathogenic potential, and in turn to the development of disease. Moreover, microbe-specific immune reactivity bears the potential to promote inflammation and immunopathology. Therefore, tight regulation of the microbiota-host interplay is of outmost importance. Fungi are now recognized as common members of the microbiota on nearly all epithelial surfaces, and recent examples revealed that - similarly to their bacterial counterparts - commensal fungal communities might have an important role in host physiology and immunity. Two of the most abundant members of the fungal microbiome are the yeasts Candida, which colonizes diverse mucosal epithelia, and Malassezia, which is abundant on the skin.

Research in the LeibundGut-lab focuses on the immune mechanisms that regulate fungal commensalism in barrier tissues and prevent fungal overgrowth and disease but may also have host adverse consequences under some conditions. We developed in vivo and in vitro experimental systems to model the intricate interactions between fungi and host under diverse physiologically relevant conditions.