Amphibian mast cells offer antifungal protection 3810

Abstract Description Disease outbreaks caused by the chytrid fungus, Batrachochytrium dendrobatidis (Bd), are compounding global amphibian declines. Bd infections are confined to amphibian skin, and there are many published studies describing the roles of amphibian skin commensals and skin-produced antimicrobial components in anti-Bd defenses. In contrast, relatively little is known about the roles of skin-resident immune cells, such as mast cells, in amphibian antifungal immunity. Indeed, mammalian mast cells reside within and serve as key immune sentinels in barrier tissues like skin. Thus, we investigated the roles of frog (Xenopus laevis) mast cells during Bd infections. Our findings indicate that frog mast cells confer antifungal protection by reducing neutrophil infiltration into Bd-infected skins, ablating inflammation-associated damage therein and promoting mucus production by cutaneous mucus glands. Akin to mammalian mast cells, which produce copious amounts of the pleiotropic interleukin-4 (IL4) cytokine, frog mast cells confer their anti-Bd protection at least in part through IL4 production. Together, our findings underscore the importance of skin-resident immune cells in amphibian anti-Bd defenses and suggest a new direction to explore host-chytrid pathogen interactions. Funding Sources Support: NSF 2147466, NSF 2131061 (LG) and NSF 2147467 (LR-S). Topic Categories Veterinary and Comparative Immunology (VET)