Eosinophils are required for clearance of <i>B. malayi</i> Mf during primary (1°), but not challenge (2°) infection.

<p><b>A.</b> Mf survival in groups of PHIL (black squares) and C57Bl/6 (open circles) mice, following primary (dotted line) and secondary (solid line) infection. Mf were counted in blood from the tail vein of mice on days 6 and 12 p.i. or in cardiac blood on day 21 p.i. (d21 PHIL mice 1° versus C57Bl/6 1° p = 0.0018) <b>B–D.</b> Cell recruitment into BALF of naïve PHIL and C57Bl/6 mice and both mouse strains mice given primary or challenge Mf infections on day 21 p.i. <b>B.</b> Mean total and differential cell recruitment into BALF. <b>C.</b> Numbers of mast cells recruited into BALF (Mean ± S.E) of naïve and infected PHIL and C57Bl/6 mice. <b>D.</b> Numbers of eosinophils recruited into BALF (Mean ± S.E) of naïve and infected PHIL and C57Bl/6 mice. <b>E.</b> Mf-specific IgG1 antibody in serum during infection of PHIL and C57Bl/6 mice (Mean ± S.E.) (dotted line represents naïve levels in both PHIL and C57Bl/6). <b>F.</b> Total IgE antibody in serum during infection of PHIL and C57Bl/6 mice (Mean ± S.E.). <b>G–I.</b> Cytokines produced by splenocytes upon stimulation with Mf antigen and measured in cell culture supernatants by ELISA 72 h later. Graphs show mean ± S.E. cytokine concentration of naïve PHIL and C57Bl/6 mice and mice 21 days post primary (1°) and challenge (2°) infections of live Mf. <b>G.</b> IFN-γ responses <b>H.</b> IL-5 responses. <b>I.</b> IL-13 responses. This figure represents data from two independent experiments with 6 individual mice per group. *represents a significant difference at p<0.05, ** p<0.01 ****p<0.0001 between groups of PHIL mice and C57Bl/6 mice given the same infection regimen.