Kinetics of eosinophilia and IgE production in experimental murine toxocariasis

Eosinophilia and immunoglobulin E (IgE) antibody are considered the first and important elements in host responses to helminth infection. Toxocara canis, which elicits prominent eosinophilia and IgE production in normal mice, may be useful in understanding the kinetics of circulating peripheral blood eosinophils and IgE antibody during infection. The onset, magnitude and duration of peripheral blood eosinophilia and total IgE production after primary T. canis infection in female outbred albino mice was investigated. Mice were either sham inoculated (controls) or were orally infected with 1000 embryonated eggs of T. canis. Patterns in leucocytic changes include significant increase in total WBC count between weeks 6 and 13 post infection (PI) with a peak on week 8 PI. Mice showed eosinophilia between weeks 2 to 17 PI with a peak on week 7. The development of eosinophilia in T. canis-infected mice was accompanied by the release of prominent level of serum IgE between weeks 2 to 21 with a peak at week 6 PI. These findings showed that eosinophilia in T. canis infected outbred mice can be T-cell dependent.