Systemic infection of zebrafish larvae with ECE1-deficient Candida albicans show improved survival compared with wild-type or ece1Δ/Δ+ECE1-infected zebrafish. (A) Zebrafish survival 24 hours after injection of 500 colony-forming unit of wild-type, ece1Δ/Δ, ece1Δ/Δ+ECE1, als3Δ/Δ or phosphate-buffered saline (PBS) as control directly into the cardinal vein. Data are presented as mean ± standard deviation (n = 4 independent experiments with at least 20 zebrafish per treatment group); statistical analysis was achieved using one-way analysis of variance with Tukey’s post hoc multiple comparison test. **, P < .01; and ***, P < .001. (B) Sagittal histological sections of periodic acid-Schiff-stained infected zebrafish showing the hyphal form of C albicans penetrating zebrafish tissue for wild-type, ece1Δ/Δ and ece1Δ/Δ+ECE1 strains compared with PBS-injected controls. Scale bars = 100 μm.

Candidalysin is required for renal neutrophil recruitment and immunopathology. (A and B) Histopathology of the kidney of mice after 1 day of infection with 2 × 10⁵Candida albicans cells of the indicated strains. Sections (A, low magnification; B, high magnification) were stained with Gomori methenamine silver (GMS). Fungal cells are filamentous and stained black, and polymorphonuclear (PMN) cells are round and dark purple. Scale bar = 50 µm. (C) Histopathology of the pelvis region (top and middle) and renal cortex (bottom) of the mouse kidney 4 days postinfection with 2 × 10⁵C albicans cells of the indicated strains. Sections were stained with GMS. Fungal cells are filamentous and stained black, and PMN cells are round and purple surrounding fungal filaments. Only wild-type C albicans invades the pelvis region with local immunopathology, whereas the ece1Δ/Δ remains in the renal cortex. Scale bar = 200 µm. (D) Myeloperoxidase (MPO) expression in kidney homogenates after 1 day of infection with 2 × 10⁵C albicans cells of the indicated strains. Results are median ± interquartile range of 2 independent experiments with 10 mice per strain. Statistical significance is indicated by ****, P < .0001 (Mann-Whitney test with Bonferroni correction for multiple comparisons).

Candidalysin-induced immunopathology is required for virulence during hematogenously disseminated candidiasis. (A) Survival of immunocompetent mice after intravenous inoculation with 2 × 10⁵ yeast phase cells of the indicated strains of Candida albicans (n  = 10). (B) Survival of leukopenic mice infected with 5 × 10⁴ wild-type or ece1Δ/Δ C albicans yeast. Statistical significance is indicated by **, P < .01 (wild-type vs ece1Δ/Δ) and ****, P < .0001 (ece1Δ/Δ+ECE1 vs ece1Δ/Δ+ECE1_Δ184–279) (Wilcoxon rank-sum test). (C) Fungal burden of the kidney, brain, spleen, and liver of leukopenic mice at 4 days postinfection after inoculation with 5 × 10⁴ wild-type or ece1Δ/Δ C albicans yeast. Results are median ± interquartile range with 6 mice per strain. Statistical significance is indicated by **, P < .01 (Mann-Whitney test). (D) Histopathology of the pelvis region (top, lower magnification; bottom, higher magnification) of the kidney of leukopenic mice after 4 days of infection with 5 × 10⁴C albicans cells of the indicated strains. Sections were stained with Gomori methenamine silver. Scale bars = 200 µm. CFU, colony-forming units.