Host and microbe adaptation underlying true fungal commensalism

Abstract Fungi are found ubiquitously in the mammalian gut however role of commensal fungi host is poorly understood. Laboratory mice used to model host-fungi interactions due ultra-clean housing they do not harbor fungi. The human fungus Candida albicans widely studied dissect host-commensal prior dysbiosis bacteria required colonize laboratory mice. Insights from such forced host-fungal unsuitable for extrapolating mechanisms underlying fungal commensalism and its breakdown. To discover natural mice, we pet-store “dirty” We that have a high burden their feces predominantly colonized by single species fungus, Kazachstania pintolopesii. Furthermore, K. pintolopesii isolated stably levels presence an intact immune system bacteria. with exhibited increased neutrophil frequency blood but did show any pathological symptoms. Surprisingly, even systemic challenge pathology indicating unique adaptations this murine host. Remarkably, significantly protected C. suggesting promote antifungal responses In summary, our work established novel unmanipulated provide insight into cellular molecular mutualism. This research was supported grants NIH (R01 DK113265), Searle Scholars program, AAI Careers Immunology Fellowship.