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Peanut protein-loaded microneedle patches are immunogenic and distinct from subcutaneous delivery

      Rationale

      Novel immunotherapy platforms are needed for peanut allergy. Epicutaneous approaches have shown promise, especially in terms of safety, but efficacy is limited to 35% of subjects following 12 months of treatment. Here, we aimed to determine the immunogenic and pharmacokinetic properties of peanut protein-loaded microneedle patches in mice.

      Methods

      Two doses (5 μg and 12.5 μg) of peanut protein-loaded microneedle patches were administered once weekly for three weeks to naive CC027 or BALB/cJ mice. Mice were bled one week following the final patch application, and peanut-specific immunoglobulins were quantified. For pharmacokinetic studies, naive BALB/cJ mice were administered 12.5 μg peanut-loaded microneedle patches or subcutaneous injection of 3, 12.5 or 100 μg peanut protein, and bled 45 minutes later to quantify Ara h 2 in serum.

      Results

      Both CC027 and BALB/cJ mice produce peanut-specific IgE, IgG1, and IgG2a post-patch applications, whereas vehicle-loaded microneedles did not induce immunoglobulin production. There were no significant differences between the 5 and 12.5 μg peanut patches in either strain. In naïve BALB/cJ mice, Ara h 2 was elevated in serum after subcutaneous injection of 3, 12.5, or 100 μg total peanut protein, but not detected after applying the 12.5 μg peanut patch.

      Conclusions

      Peanut protein administered via microneedles into the dermal layer of skin causes an immune response leading to production of peanut-specific immunoglobulins. The absence of Ara h 2 in the serum indicates that peanut protein is not readily absorbed into circulation. This data suggests that microneedle-based immunotherapy may be a safe way to administer peanut-specific immunotherapy.