Figure 6.
Allergy suppression by infection depends on IFNγ but not on γδ T cells. (a) Levels of oocysts collected from the feces of wt adult mice infected with 100 oocysts (left) or IFNγ−/− mice infected with 10 oocysts (right). A similar level of infection is seen in both. IFNγ−/− mice were, therefore, infected with 10 oocysts and OVA-sensitized and challenged as in Figure 1a. (b) Levels of CCR3-positive cells infiltrating into the BALF of OVA or PBS-treated infected (diamonds, right) or uninfected (diamonds, left) IFNγ−/− mice. Levels of eotaxin-2 mRNA in IFNγ−/− mice infected (diamonds, right) or uninfected (diamonds, left) with E. vermiformis are shown in (c). Figure represents cumulative data from two independent experiments. TCRδ−/− mice were infected, sensitized, and challenged as described in Figure 1a. Previously infected TCRδ−/− mice (diamonds, right hand side) or uninfected TCRδ−/− mice (diamonds, left hand side) subsequently sensitized and challenged with OVA or PBS were assessed for (d) IL-5 levels in the BALF, (e) CCR3-positive cell infiltration into the BALF, and (f) eotaxin-1 mRNA in the lung. All AAI parameters tested were induced by OVA sensitization and challenge in the TCRδ−/− mice and all were reduced by previous infection with E. vermiformis.