Fig. 5: IFN-γ supplementation promotes early intestinal accumulation of Th2/1 cells and impacts larval fitness.

Adult BALB/c mice (1.5 mo) were infected with H. polygyrus and treated with rIFN-γ (2.5 μg twice a day) during the first five days of infection and dissected at day 6 post infection. T-bet and GATA-3 expression (a), IL-4 and T-bet expression (b) and IFN-γ versus GATA-3 expression (c) in siLP-derived CD4+ FoxP3− cells. Stacked bars report the percentage of total GATA-3+, IL-4+ and IFN-γ+ cells, deciphering between T-bet+/− and GATA-3+/− cells as indicated. Cells were stimulated with PMA/ionomycin. Data from three independent experiments (n naïve = 6; n infected = 9–10 mice/group) are reported as mean ± SD. d Experimental setup. Small intestinal explants were cultured at 37 °C and the number of 4^th stage larvae migrating from host tissue was determined after 4 h. Pictures show a freshly prepared small intestinal explant with L4 embedded in the tissue (white arrows); L4 remaining in the tissue after 4 h of cultivation; and partially egressed 4^th stage larvae. Graph reports L4 migrated from the tissue within 4 h (mean and individual mice), expressed as the percentage of total larvae in the tissue explant. Data from two independent experiments are pooled (n = 7–8 mice/group). Bars report the mean, circles represent individual mice. Statistical analysis was performed using one-way ANOVA and Tukey’s multiple comparisons test or Kruskal–Wallis test and Dunn’s multiple comparisons test in a–c and unpaired t test in d. The statistical significance comparing each sub-population in a–c is shown by asterisks in the corresponding colors. Black asterisks in c indicate significantly different overall frequencies of IFN-γ+ producing cells comparing infection controls and IFN-γ-treated mice. **p ≤ 0.01, ****p ≤ 0.0001.