Soy immunotherapy for peanut-allergic mice: modulation of the peanut-allergic response.

Background: Allergen-specific immunotherapy (IT) is an effective therapeutic modality to prevent further anaphylactic episodes in patients with insect sting hypersensitivity and is being investigated for peanut allergy. So far, peanut-specific IT has been unsuccessful because of the side effects of therapy. Soybean seed storage proteins share significant homology with the respective peanut allergens.

Objective: This study was undertaken in mice to investigate whether specific doses of soybean would desensitize peanut-allergic mice.

Methods: C3H/HeJ mice were sensitized to peanut with 3 intraperitoneal (IP) injections of crude peanut extract. The mice were desensitized by IP injections with either crude peanut or soybean extract for 4 weeks, 3 times a week. Controls included placebo desensitization with PBS and naive mice. After 2 weeks of rest, mice were challenged IP with crude peanut extract. Thirty minutes later, symptom scores and body temperatures were recorded. Serum immunoglobulins, peanut-induced splenocyte proliferation, and secreted cytokines were measured before and after desensitization.

Results: The clinical symptoms in the soybean- and peanut-desensitized animals were markedly reduced compared with the placebo-treated mice. Specific IgG1 levels to crude peanut were significantly lower in the soy IT group than in the peanut IT group. The cellular response to crude peanut was also downregulated in the soy IT group, as shown by decreased peanut-specific stimulation indices and a cytokine profile skewed toward a T H 1 response.

Conclusions: Soy IT can be used to desensitize/downregulate peanut-specific response in peanut-allergic mice and could provide a new therapeutic intervention for peanut allergy.