Figure 4: Lung immunity towards N. brasiliensis reinfection is dependent on IL-13-producing T cells and ILC2s.

(a,b) Number of N. brasiliensis larvae in the airways, measured in BALF (dark grey) or lung parenchyma (light grey) of Stat6^−/− (a), Il-4^−/− (b) or wild-type (B6) mice 2 days post-primary (Nb) or (Nb+Nb) i.v. reinfection (n=5 mice, mean+s.e.m., representative of two independent experiments, ANOVA on total larvae number). (c) Number of lung larvae 2 days post infection in C56Bl/6 or Il-4^−/− mice treated for 1 week of IL-13 blockade before i.v. reinfection or with matched isotype control antibody (AbbVie, n=4 mice, mean+s.e.m., ANOVA). (d) Representative flow cytometry plots of IL-13⁺ cells in i.v.-reinfected–infected wild-type and 4C13R transgenic mice. All cell types are identified as live and DS-Red⁺. Basophils are further identified by expression of CD200R3 and CD45^mid. ILC2s are identified as lineage negative CD90⁺ CD25⁺. CD4⁺ T cells are identified as CD90⁺ CD4⁺. (e) Number of CD4⁺ T cells (dark grey bars) and ILC2s (light grey bars) in the lung tissue of naïve 4C13R mice, at days 2 after i.v. primary infection (Nb) and 30 post-primary s.c. infection (Nb+30 days) and at 2 days after i.v. reinfection (Nb+Nb, n=5, mean+s.e.m., representative of two independent experiments, ANOVA). (f) Number of IL-13⁺ CD4⁺ T cells and ILC2s as identified in d (n=5, mean+s.e.m., representative of two independent experiments, ANOVA). (g) Histogram of CD25 expression on ILC2s identified in d. NS, non-significant; P>0.05; *P<0.05; **P<0.01; ***P<0.001.