Rapid induction of allergen‐blocking IgG in dogs vaccinated with plant‐based, Der f 2‐expressing bioparticles

BackgroundAllergen‐carrying virus‐like particles are effective and safe means of allergen immunotherapy (AIT) in rodent models.ObjectiveTo study the development of allergen‐blocking immunoglobulin (Ig)G in dogs injected with Der f 2‐carrying enveloped plant‐based bioparticles (eBPs).Materials and MethodsLaboratory beagle dogs were injected intradermally (ID) or subcutaneously (SC) with Der f 2‐eBP three times at 2‐week intervals. A basophil mediator release assay was used to compare the reactivity of Der f 2‐eBPs to that of recombinant Der f 2. Allergen‐specific IgG serum levels were determined by immunoblotting and ELISA. The allergen‐blocking potential of postvaccination IgG was assessed by Pet Allergy Xplorer (PAX) macroarray and basophil mediator release inhibition assays.ResultsThe amount of Der f 2 eBPs needed to induce basophil activation was 1000‐fold higher than that of the soluble natural allergen. In both immunisation groups, eBP injections caused no adverse events and induced Der f 2‐specific IgG, first detected on Day (D)14 and peaking on D41. The co‐incubation of sera with a Der f 2‐IgE‐rich canine serum pool resulted in a mean PAX inhibition of 70% (ID) to 80% (SC) on D41. For both groups, the inhibition of basophil mediator release reached 75% on D28 and D41. The percentage inhibition of PAX and mediator release correlated significantly with Der f 2 IgG levels.Conclusion and Clinical RelevanceIntradermal and subcutaneous injections of Der f 2‐eBPs were safe and increased Der f 2‐specific IgG. The clinical benefit of immunotherapy will be evaluated in future trials enrolling atopic dogs allergic to house dust mites.