Diurnal regulation of the host response to A. fumigatus infection. C57BL/6 wild-type mice (n = 3–7 mice per group from two independent experiments) were infected intranasally with live A. fumigatus conidia at two ZT, and assessed at 1, 3, and 7 day post-infection (dpi), as described in the experimental plan (A). (B) Lung fungal growth studied by the count of colony forming units (log10 CFU). Black bars indicate the geometric mean (n = 3–7). P-values were generated by two-way ANOVA test, Bonferroni post-hoc test, significant changes are shown. *P < 0.05, ***P < 0.001. (C) Lung histology studied by periodic acid–Schiff staining (left, scale bars 200 μm), and percentage of polymorphonuclear neutrophils studied by May–Grünwald Giemsa staining of cells obtained from BAL (insets). (D) Lung fungal infiltration at 3 dpi studied by Grocott-Gomori methenamine staining (right, scale bars 100 μm). (E) BAL cellular morphometry, expressed as means of total and differential cell counts ± SEM are presented. P-values were generated by two-way ANOVA test, Bonferroni post-hoc test, significant changes are shown. **P < 0.01, ****P < 0.0001 for PMN, ⁺P < 0.05 for total cells. (E) Mouse pro-inflammatory cytokines measured by multiplex immunoassay in lung homogenates. Results shown as mean ± SEM (n = 3). P-values were generated by two-way ANOVA test, Bonferroni post-hoc test. Significant changes are shown. *P < 0.05, **P < 0.01.