Amphibian immune defenses against an ancient fungal pathogen
The main focus of my research is host pathogen interactions using amphibian model systems. Currently, my laboratory is pursuing a number of questions concerning the nature of innate and adaptive immune defenses in frog skin. Understanding the immune defense mechanisms of amphibians has taken on increased importance in recent years because of the urgent problem of global amphibian declines. Little is known about the conventional adaptive immune response against Batrachochytrium dendrobatidis, a skin pathogen associated with global amphibian declines. Our ongoing studies have shown that B. dendrobatidis releases factors which inhibit lymphocyte responses. Current research investigates the specific mechanisms by which this fungus escapes immune clearance. Another focus of my research is the study of antimicrobial peptides (AMPs) in frog skin in defense against bacterial, viral, and fungal pathogens. We use MALDI-TOF mass spectrometry to examine the profiles of skin peptides and growth inhibition assays to test the ability of purified AMPs and natural mixtures of skin peptides to interfere with growth of specific pathogens that have been associated with global amphibian declines. We continue to try to determine whether some species have better peptide defenses against specific pathogens than other species. Another newer area of research is the effects of temperature on immune defenses of local Tennessee amphibians. This relates to the question of how climate change may impact southern amphibians. A new species of Batrachochytrium (B. salamandrivorans) threatens native amphibian species. With collaborators, we are also studying the role of skin microbiota as protectors of amphibians fromBatrachochytrium pathogens.