title: The invasive chytrid fungus of amphibians paralyzes lymphocyte responses.
abstract: The chytrid fungus, Batrachochytrium dendrobatidis, causes chytridiomycosis and is a major contributor to global amphibian declines. Although amphibians have robust immune defenses, clearance of this pathogen is impaired. Because inhibition of host immunity is a common survival strategy of pathogenic fungi, we hypothesized that B. dendrobatidis evades clearance by inhibiting immune functions. We found that B. dendrobatidis cells and supernatants impaired lymphocyte proliferation and induced apoptosis; however, fungal recognition and phagocytosis by macrophages and neutrophils was not impaired. Fungal inhibitory factors were resistant to heat, acid, and protease. Their production was absent in zoospores and reduced by nikkomycin Z, suggesting that they may be components of the cell wall. Evasion of host immunity may explain why this pathogen has devastated amphibian populations worldwide.
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.
authors.forename: J Scott
authors.initials: JS
authors.lastname: Fites
authors.forename: Jeremy P
authors.initials: JP
authors.lastname: Ramsey
authors.forename: Whitney M
authors.initials: WM
authors.lastname: Holden
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Collier
authors.forename: Danica M
authors.initials: DM
authors.lastname: Sutherland
authors.forename: Laura K
authors.initials: LK
authors.lastname: Reinert
authors.forename: A Sophia
authors.initials: AS
authors.lastname: Gayek
authors.forename: Terence S
authors.initials: TS
authors.lastname: Dermody
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Aune
authors.forename: Kyra
authors.initials: K
authors.lastname: Oswald-Richter
authors.forename: Louise A
authors.initials: LA
authors.lastname: Rollins-Smith
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology; D000663:Amphibians / Q000276:immunology* / Q000382:microbiology*; D000818:Animals; D017209:Apoptosis / Q000276:immunology; D049109:Cell Proliferation; D008411:Chytridiomycota / Q000472:pathogenicity*; D054884:Host-Pathogen Interactions / Q000276:immunology*; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology*; D009181:Mycoses / Q000276:immunology / Q000662:veterinary*; D013172:Spores, Fungal / Q000472:pathogenicity; D014982:Xenopus laevis
chemical_list: D000617:Aminoglycosides; C011952:nikkomycin