CD4+ T cells induced by virus-like particles expressing a major T cell epitope down-regulate IL-5 production in an ongoing immune response to Der p 1 independently of IFN-γ production

It has been previously demonstrated that hybrid Ty virus-like particles (VLP) prime effective CD8 and CD4 T cell responses. In this study, we investigated the effect of treating mice with Ty VLP carrying the immunodominant epitope of Der p 1 after sensitizing them to the group 1 allergen of the house dust mite Dermatophagoides pteronyssinus (Der p 1), under conditions that induce Th2 immunity. We show that i.p. treatment with the hybrid VLP abrogated allergen-specific IL-5 production and reduced allergen-specific cell proliferation. This suppression of the response was mediated by CD4 T cells and was not accompanied by an increase in IFN-γ production.