Amphibian Immune Defenses against Batrachochytrium dendrobatidis: a War between Host and Pathogen

Abstract

Populations of amphibians around the world have experienced devastating declines in the last few decades. A newly emerging fungal pathogen, Batrachochytrium dendrobatidis, has been implicated as one cause of these declines. Some frog species, such as Xenopus laevis, are considered resistant to lethal infections of B. dendrobatidis, whereas other species are susceptible. My work focused on whether innate or adaptive immune defenses, or both, play a role in determining a species’ overall resistance to fatal B. dendrobatidis infections. My research concluded that innate antimicrobial peptide defenses in the skin play a critical role in resistance, as does an irradiation-sensitive component of the adaptive immune system. However, further research found that B. dendrobatidis has the ability to attenuate adaptive responses by preventing proliferation of activated lymphocytes via the induction of apoptosis in these cells. My overall work suggests that the interplay between the strength of both innate and adaptive immune responses after B. dendrobatidis exposure and the capacity of B. dendrobatidis to impair adaptive immunity dictate a species’ overall resistance to B. dendrobatidis infections.