PAS-1, a protein from Ascaris suum, modulates allergic inflammationvia IL-10 and IFN-c, but not IL-12

ABSTRACT

Helminths and their products have a profound immunomodulatory effect upon the inductive and effectorphases of inflammatory responses, including allergy. We have demonstrated that PAS-1, a protein isolatedfrom Ascaris suum worms, has an inhibitory effect on lung allergic inflammation due to its abilityto down-regulate eosinophilic inflammation, Th2 cytokine release and IgE antibody production. Here,we investigated the role of IL-12, IFN-c and IL-10 in the PAS-1-induced inhibitory mechanism using amurine model of asthma. Wild type C57BL/6, IL-12 / , IFN-c / and IL-10 / mice were immunized withPAS-1 and/or OVA and challenged with the same antigens intranasally. The suppressive effect of PAS-1was demonstrated on the cellular influx into airways, with reduction of eosinophil number and eosinophilperoxidase activity in OVA + PAS-1-immunized wild type mice. This effect well correlated with a significantreduction in the levels of IL-4, IL-5, IL-13 and eotaxin in BAL fluid. Levels of IgE and IgG1antibodies were also impaired in serum from these mice. The inhibitory activity of PAS-1 was alsoobserved in IL-12 / mice, but not in IFN-c / and IL-10 / animals. These data show that IFN-c andIL-10, but not IL-12, play an important role in the PAS-1 modulatory effect.