Figure 1.

Strongyloides venezuelensis-experienced mice develop an increased pulmonary inflammation and a resistance against Nippostrongylus brasiliensis infection. (A) Experimental workflow for sequential nematode infection. S. venezuelensis (Sv)-infected or uninfected mice were inoculated with 500 N. brasiliensis (Nb) L3 at day 28. B6; C57BL/6, WT; wild type, sac; sacrificed. (B) The number of lung stage N. brasiliensis larva. Two days after N. brasiliensis infection, migrating larva were isolated from the lungs and counted (n = 11). cont, control (uninfected at day 0). Pooled data from two independent experiments are shown (Mean ± SD). (C) The numbers of worms in the intestine were counted at indicated days (n = 5). (D) The numbers of eggs per gram feces (EPG) from each group at day 7 post-N. brasiliensis infection (n = 7). (E–G) The numbers of eosinophils and ILC2s (E), the amounts of IL-5 and IL-13 in the BALF (F), and the Il5, Il13, and Il33 mRNA expression levels in the lungs as analyzed by Q-PCR (G) from day 35 are shown (n = 4–5). uninf.; uninfected at day 28. Statistical analyses were conducted using two-way ANOVAs with Bonferroni post-hoc tests (B,E,G), Wilcoxon matched-pairs signed rank tests, and two-tailed (C) or unpaired t-tests (F). Data are representative of two independent experiments. (H) C57BL/6 WT mice (n = 5–6) were infected with 5000 L3 S. venezuelensis at day 0. The numbers of ILC2s, eosinophils, CD3⁺/B220⁺ cells, and monocytes among the BALF cells at the indicated days were analyzed by flow cytometry (FACScalibur). Cell populations were defined as follows: ILC2s, FSC^loSSC^loLin(CD3, CD4, CD8, CD19, NK1.1, IgE, Gr-1, siglecF)⁻Sca-1⁺ST2⁺; Eosinophils, CD45⁺CD3⁻B220⁻CCR3⁺, CD3/B220: CD45⁺CCR3⁻CD3⁺/B220⁺; and Monocytes, CD45⁺Autofluorescence^high. Data were compared with day 0 data by one-way ANOVA. Data are representative of two independent experiments.