Figure 1.

The reduced worm burden in trickle-infected C57Bl/6 mice is associated with elevated serum IgE. 6-8 week old C57Bl/6 and BALB/c mice were infected with 200 H polygyrus larvae according to the bolus and trickle infection regimes. (A) Trickle infection regime: mice are infected with 200 larvae in total, but in multiple doses over the course of infection (in grey). Doses of ~33 larvae are trickled on days 0, 2, 4, 6, 8 and 10 post-infection. There is a 10-day window after the final dose to allow parasites to fully develop into adults and migrate from the intestinal tissue to the intestinal lumen. (B) Adult worms were counted in the small intestine using a dissection microscope. (C) Single cell suspensions were isolated from the mesenteric lymph nodes and spleens. Viable cell numbers in the MLN (left) and SPL (right). Single cell suspensions were either used for flow cytometry or cultured for 48 hours in the presence of H polygyrus antigen. (D) Percentage of Foxp3⁺ cells within the CD4+ population of MLN cells were measured by flow cytometry. (E) IL-4 (MLN and SPL) and (F) IL-13 (MLN and SPL) cytokine levels were measured in the supernatant by ELISA. Serum antibody levels were measured by ELISA for (G) parasite specific IgG1 and (H) total IgE. Levels in naïve controls were undetectable for parasite specific IgG1. For all panels except D, graphs represent pooled data from 2 experiments, bars represent the median, with a minimum of 3 mice per group per experiment. For panel D, each circle represents one experiment using cells pooled from 5 mice. BALB/c mice (white mouse) and C57Bl/6 mice (black mouse) were infected according to the bolus (black circles) and trickle (white circles) regimes. A normality test was performed (Anderson-Darling) followed by a Kruskal Wallis test with Dunn’s multiple comparisons test to test for statistical significance between trickle and bolus groups; for panel (D), a paired T-test was performed; n.s., not significant; *p<0.05, ****p<0.0001.