title: Candida albicans biofilms do not trigger reactive oxygen species and evade neutrophil killing.
abstract: Neutrophils are found within Candida albicans biofilms in vivo and could play a crucial role in clearing the pathogen from biofilms forming on catheters and mucosal surfaces. Our goal was to compare the antimicrobial activity of neutrophils against developing and mature C. albicans biofilms and identify biofilm-specific properties mediating resistance to immune cells. Antibiofilm activity was measured with the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)2H-tetrazolium-5-carboxanilide assay and a molecular Candida viability assay. Reactive oxygen species generation was assessed by measuring fluorescence of 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester in preloaded neutrophils. We found that mature biofilms were resistant to leukocytic killing and did not trigger reactive oxygen species, even though neutrophils retained their viability and functional activation potential. Beta-glucans found in the extracellular matrix negatively affected antibiofilm activities. We conclude that these polymers act as a decoy mechanism to prevent neutrophil activation and that this represents an important innate immune evasion mechanism of C. albicans biofilms.
authors.affiliation: Department of Oral Health and Diagnostic Sciences, Division of Periodontology, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT 06030-1710, USA.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Xie
authors.forename: Angela
authors.initials: A
authors.lastname: Thompson
authors.forename: Takanori
authors.initials: T
authors.lastname: Sobue
authors.forename: Helena
authors.initials: H
authors.lastname: Kashleva
authors.forename: Hongbin
authors.initials: H
authors.lastname: Xu
authors.forename: John
authors.initials: J
authors.lastname: Vasilakos
authors.forename: Anna
authors.initials: A
authors.lastname: Dongari-Bagtzoglou
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D002176:Candida albicans / Q000276:immunology* / Q000472:pathogenicity / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D057131:Immune Evasion; D050296:Microbial Viability; D009504:Neutrophils / Q000276:immunology*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species