Department of Biological Sciences, The George Washington University, Washington, United States
Dustin T Howard
Department of Biological Sciences, The George Washington University, Washington, United States
Netra Ranganathan
Department of Biological Sciences, The George Washington University, Washington, United States
Lindsey K Gentry
Center for Conservation Genomics, Smithsonian National Zoo & Conservation Biology Institute, Washington, United States
Amulya Yaparla
Department of Biological Sciences, The George Washington University, Washington, United States
Namarta Kalia
Department of Biological Sciences, The George Washington University, Washington, United States
Mira Zelle
Department of Biological Sciences, The George Washington University, Washington, United States
Elizabeth J Jones
Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, United States
Anju N Duttargi
Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, United States
Louise A Rollins-Smith
Departments of Pathology, Microbiology and Immunology, and of Pediatrics, Vanderbilt University School of Medicine, Nashville, United States; Department of Biological Sciences, Vanderbilt University, Nashville, United States
Carly R Muletz-Wolz
Center for Conservation Genomics, Smithsonian National Zoo & Conservation Biology Institute, Washington, United States
Global amphibian declines are compounded by deadly disease outbreaks caused by the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Much has been learned about the roles of amphibian skin-produced antimicrobial components and microbiomes in controlling Bd, yet almost nothing is known about the roles of skin-resident immune cells in anti-Bd defenses. Mammalian mast cells reside within and serve as key immune sentinels in barrier tissues like skin. Accordingly, we investigated the roles of Xenopus laevis frog mast cells during Bd infections. Our findings indicate that enrichment of X. laevis skin mast cells confers anti-Bd protection and ameliorates the inflammation-associated skin damage caused by Bd infection. This includes a significant reduction in infiltration of Bd-infected skin by neutrophils, promoting mucin content within cutaneous mucus glands, and preventing Bd-mediated changes to skin microbiomes. Mammalian mast cells are known for their production of the pleiotropic interleukin-4 (IL4) cytokine and our findings suggest that the X. laevis IL4 plays a key role in manifesting the effects seen following cutaneous mast cell enrichment. Together, this work underscores the importance of amphibian skin-resident immune cells in anti-Bd defenses and illuminates a novel avenue for investigating amphibian host–chytrid pathogen interactions.
