Cellular Responses of Candida albicans to Phagocytosis and the Extracellular Activities of Neutrophils Are Critical to Counteract Carbohydrate Starvation, Oxidative and Nitrosative Stress
Figure 5
ROS induction and survival of deletion mutants cta1Δ/Δ, grx2Δ/Δ and trx1Δ/Δ.
(A) a. Upon neutrophil confrontation with strain grx2Δ/Δ, ROS accumulated. Deletion mutant lacking the catalase coding gene, cta1Δ/Δ, had only a slight and not significant increase in ROS accumulation, when compared to the wild type strain (CAI4 + CIp10). A representative result of one replicate is shown. b. Quantification of the area under the curve. Stimulation of neutrophils with grx2Δ/Δ but not with cta1Δ/Δ led to significant accumulation of ROS. Unstimulated and PMA-stimulated neutrophils were used as negative and positive controls, respectively. The average of three independent experiments is presented. c. C. albicans mutant grx2Δ/Δ is reduced in the wild type survival capacity when exposed to neutrophils. In contrast, cta1Δ/Δ did not show a significant decrease in the sensitivity to neutrophils. Fungal cells were exposed to neutrophils for 3 h. Results from four independent replicates are shown. Survival of the wild type strain was set to 100%. (B) a. ROS production in response to trx1Δ/Δ. Neutrophil-derived ROS are slightly decreased upon stimulation with a trx1Δ/Δ mutant, when compared to the isogenic WT strain (SN148 + CIp30). b. Quantification of the area under the curve. Data represent the average of three independent experiments. c. The sensitivity of the trx1Δ/Δ mutant towards neutrophil killing was not clearly affected as compared to the WT. Results from three independent replicates are shown. Survival of the WT was set to 100%. *P≤0.05; **P≤0.01; compared to the control.