Host mechanisms against the abundant skin commensal yeast Malassezia

Malassezia in hair follicle

The skin, one of our body’s largest organs, is home to millions of microbes, which in addition to bacteria also include fungi. The yeast Malassezia is by far the most abundant fungal organism found on human and animal skin. Tight control of the growth of Malassezia is required to prevent exuberant masses of fungus on our skin or invasion of the fungus into tissues and the circulation, which would result in disease. Commensal organisms are constantly kept in check by the immune system. Which immune mechanisms are active against Malassezia remains largely unclear. This project investigates the interplay of the skin-commensal fungus and the mammalian host during skin homeostasis. Our focus is on the interleukin-17 (IL-17) pathway, which is essential for maintaining commensalism and preventing fungal overgrowth on the normal skin. We study the mechanisms of IL-17 immune activation and the impact of IL-17-mediated effector functions on the fungus in the skin. Together, this project will clarify how  fungal homeostasis is maintained at the host interface.

Funding: Swiss National Science Foundation

LEGEND: Malassezia pachydermati in a hair follicle of the ear skin.