Methods: Mice were sensitized to peanut or egg proteins to induce a Th2 and IgE allergic phenotype followed by three monthly intranasal immunizations with allergen and adjuvant. Mice were then challenged with allergen, and symptoms of allergic reactions were measured.
Results: Therapeutic intranasal immunizations resulted in decreased Th2 cytokines and IgG1 and IgE, as well as increased Th1/Th17 immune responses. Importantly, following allergen challenge, mice that received the allergy vaccines showed significant reductions in allergic hypersensitivity and anaphylaxis, including decreases in mast cell degranulation and inflammation. Additionally, the immunization significantly increased IL-10 production as well as regulatory T cells, suggesting a mechanism for the suppression of Th2 immunity.
Conclusions: Induction of Th1/Th17 immunity can suppress Th2 allergic responses, likely through IL-10 associated regulatory cells, and protect against anaphylaxis. This modification of allergen-specific immune responses may induce memory and cause more long-lived suppression of allergy than desensitization.