Inhibition of Eosinophil Infiltration and Humoral Immune Reaction by Ketotifen in BALB/c Mice Infected with Echinostoma hortense

Eosinophils play an essential role in allergy reaction after parasite infection. To examine the immune reaction induced by eosinophils, we investigated the allergy reaction in BALB/c mice infected with Echinostoma hortense's metacercariae, as well as the effect of ketotifen, an anti-allergy drug, on eosinophil immune reaction in the villi of host intestine. The worm recovery rate was higher in ketotifen-treated mice than in untreated mice and the worms in ketotifen-treated mice survived longer than those in untreated mice. The antibody titer in the serum of ketotifen-treated mice was very low. Especially, Echinostoma hortense infection strongly increased serum IgE level and eosinophil infiltration into the villi of the mouse intestine. Ketotifen treatment suppressed eosinophil infiltration into the infected areas and inhibited IL-4 production. The reduced IL-4 production may be related with the reduction of IgE, IgG1 and IgG2 production. In conclusion, ketotifen inhibited eosinophil infiltration functioning in the allergy reaction induced by parasite infection and the expression of immunoglobulins and cytokines.