Influence of endogenous pro-inflammatory cytokines on neutrophil-mediated damage of Candida albicans pseudohyphae, quantified in a modified tetrazolium dye assay.
Wieland, C.W.
Verschueren, C.M.M.
Joostent, L.A.
EBP 3: Effective Primary Care and Public Health; N4i 1: Pathogenesis and modulation of inflammation; N4i 2: Invasive mycoses and compromised host; NCMLS 1: Infection and autoimmunity; UMCN 4.1: Microbial pathogenesis and host defense; UMCN 4.2: Chronic inflammation and autoimmunity
For quantitative assessment of polymorphonuclear granulocyte (PMN)-mediated pseudohyphal damage, an improved tetrazolium (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide; XTT) dye assay was developed. The modified assay proved to be a reliable indicator of viable pseudohyphal inoculum sizes. In addition, the influence of various endogenous pro-inflammatory cytokines on the capacity of PMN to damage Candida albicans pseudohyphae was investigated. PMN obtained from mice in which the genes encoding for tumor necrosis factor-alpha/lymphotoxin-alpha (TNF/LT), interferon-gamma (IFNgamma), interleukin (IL)-1alpha, or IL-1beta were disrupted, showed a significantly reduced pseudohyphal damage capacity in comparison with control PMN. The reduction amounted 25% for TNF-/- LT-/-, 11% for IFNgamma-/-, 21% for IL-1alpha-/-, and 34% for IL-1alpha-/-beta-/- PMN. In contrast, deficiency of IL-12 or IL-18 did not result in a diminished capacity to damage pseudohyphae and the capacity of PMN to damage Candida pseudohyphae was even slightly increased by 10% in IL-18-/- mice. These data suggest that endogenous pro-inflammatory cytokines are able to modulate antihyphal activity of PMN, the main effector cells against disseminated candidiasis by virtue of their capacity to kill both Candida blastoconidia and pseudohyphae.