Indeed, it has been demonstrated that methacoline-induced AHR in mouse models correlates with an antigen-specific Th2 immune response [46–49], but not with severity of eosinophilic lung inflammation [47,50]. It has been reported that IL-10 is the main cytokine involved in suppression of Th2 allergic inflammation due to helminth infection [12,40]. We evaluated the levels of this cytokine in BAL of sensitized mice. Although the levels of this cytokine were higher only

in mice immunized with Sm22·6, the ratio IL-10/IL-4 was higher in mice immunized Opaganib datasheet with Sm22·6 and also with PIII compared to non-immunized mice. In fact, it is possible that IL-10 may not be the only mechanism involved in down-modulation of the allergic inflammatory response in S. mansoni antigen-immunized

mice. Indeed, suppression of inflammatory cell migration to the airways and down-modulation of IgE production were seen in mice immunized with Sm29 compared to non-immunized mice, despite the low levels of IL-10 in BAL. The possibility that there are other modulatory mediators that act independently of IL-10- is supported by our previous demonstration that regulatory T cells of S. mansoni-infected mice protect against allergen-induced airway inflammation through an IL-10-independent mechanism [38]. While infection with Nippostrongylus brasiliensis find more has been found to suppress airway inflammation in an IL-10-dependent manner [51], other researchers have found that N. brasiliensis products inhibit an allergic

response in the airways of mice, independently of the levels of IL-10 [52]. Therefore, for the Quisqualic acid same parasites, different modulatory mechanisms of the allergic response may exist. In this study the frequency of CD4+FoxP3+ T cells was significantly higher in mice immunized with Sm22·6 and PIII. There was a trend towards increased frequency of these cells in mice immunized with Sm29, compared to non-immunized mice. However, only in mice immunized with Sm22·6 was there a significantly higher frequency of CD4+FoxP3+ T cells expressing IL-10 compared to non-immunized mice. In agreement with these data, higher levels of IL-10 in BAL relative to non-immunized group was also observed only in mice immunized with Sm22·6. It is possible that the CD4+FoxP3+ T cells could be acting through cell–cell contact to inhibit Th2- inflammatory mediators in the other groups of mice. Indeed, in the group of mice immunized with Sm29 we did not observe an increase in IL-10 production; nevertheless, there was a reduction in eosinophil infiltration and in the OVA-specific IgE levels. We found no increase in the levels of the Th1 cytokines IFN-γ and TNF in the BAL of immunized mice compared to non-immunized ones. These data argue in favour that down-modulation of the Th2 response by the parasite antigens was not due to an increase in Th1 response.