A comparative study of microneedle-based cutaneous immunization with other conventional routes to assess feasibility of microneedles for allergy immunotherapy

Feasibility of microneedles (MNs) for cutaneous allergen specific immunotherapy (ASI) is demonstrated by comparing against currently practiced subcutaneous (SC) allergen immunotherapy, and the intramuscular (IM) and intraperitoneal (IP) routes. In Balb/c mice with ovalbumin (Ova, 25 μg) as the allergen MNs-Ova without alum induced anti-Ova IgG response comparable to IM but higher than SC and IP groups (250 μg alum was additionally used for SC, IM and IP groups). MNs-Ova induced higher anti-Ova IgG1 and IgG2a responses in comparison to other routes; however IgG2b and IgG3 responses were significantly lower than the IP group. As in SC group, anti-Ova IgE and IgA were low for MNs-Ova. Furthermore, MNs-Ova induced expression of IL-5, IL-13, IFN-γ and IL-1β cytokines in serum, but at significantly lower levels than other routes. Overall, MNs-Ova induced allergen-specific IgG antibodies, and activated the Th1 pathway (evidenced by higher IgG2a levels), suggesting their potential use for painless ASI.