Needle-free Epicutaneous For t 2 DNA Vaccine is Effective for Preventing
and Treating Biting Midge (Forcipomyia taiwana) allergy in a
murine model
Abstract
Backgrounds: Allergen-specific immunotherapy (ASIT) is capable of
inducing immune tolerance to the corresponding allergen, thereby
enabling treatment of the root cause of the allergic disease. As the
treatment course of protein-based vaccines for ASIT is time-consuming,
an easily administered epicutaneous anti-allergic DNA-based vaccine is
an attractive method, especially during the COVID-19 pandemic. Methods:
We established a mouse model allergic to the biting midge, Forcipomyia
taiwana, to test the concept of the epicutaneous DNA vaccine. The
experiments were designed using two approaches: therapeutic and
prophylactic. Mice were patched with 25 μg For t 2 DNA vaccine patches
for one hour with a total of three treatments spaced one week apart.
Scratch bouts after For t 2 allergen challenge were used as a clinical
surrogate of itch and biomarkers for allergic inflammation were examined
by ELISA, RT-PCR, and histopathology. Results: We found that after
epicutaneous DNA vaccination, the mice significantly improved with
respect to allergen-induced scratch. For t 2-specific IgE, mRNA, and
protein of IL-13 and eosinophils infiltration in the targeted skin
decreased. For t 2-specific -IgG2a and mRNA expression of FOXP3
increased. Conclusions: We demonstrated the first needle-free
epicutaneous DNA vaccine patch that is effective in preventing as well
as treating biting midge allergy in a murine model. The mice showed
improvements in their allergic condition both clinically as well as in
allergic inflammation. The mode of this anti-allergic DNA vaccine may
have the potential for use in other specific immunotherapies for other
allergens.