Immunotherapies for patients with
food allergy have shown some success in limiting allergic responses. However, these approaches require lengthy protocols with repeated
allergen dosing and patients can relapse following discontinuation of treatment. The purpose of this study was to test if a single dose of an adeno-associated virus (AAV) vector can safely prevent and treat
egg allergy in a mouse model. AAV vectors expressing
ovalbumin (OVA) under an ubiquitous or liver-specific promoter were injected prior to or after epicutaneous sensitization with OVA. Mice treated with either AAV8-OVA vector were completely protected from
allergy sensitization. These animals had a significant reduction in
anaphylaxis mediated by a reduction in OVA-specific
IgE titers. In mice with established OVA
allergy, allergic responses were mitigated only in mice treated with an AAV8-OVA vector expressing OVA from an ubiquitous promoter. In conclusion, an AAV vector with a liver-specific promoter was more effective for
allergy prevention, but higher OVA levels were necessary for reducing symptoms in preexisting
allergy. Overall, our AAV gene
immunotherapy resulted in an expansion of OVA-specific FoxP3+ CD4+ T cells, an increase in the regulatory
cytokine IL-10, and a reduction in the
IgE promoting
cytokine IL-13.