A Dissolvable Microneedle Formulation of Bordetella pertussis Subunit Vaccine: Translational Development and Immunological Evaluation in Mice

This study evaluated the feasibility of microneedle (MN) technology as an alternative approach for pertussis toxin (PT) vaccine delivery. The characterization of PT vaccine MNs ensured sufficient mechanical property to deliver antigens to intradermal tissues of mice for intensive stimulations at the targeting of immune cells. The histological examination suggested that PT vaccine MNs successfully embedded into the mouse dermis to a depth of approximately 330 μm. The in vivo fluorescence imaging showed the sustained and longer release of antigens through MN patches compared to a direct subcutaneous (s.c.) injection, thus resulting in the quick generation of a high level of PT-specific IgG after the first immunization. Moreover, similar IgG levels could be elicited by these two delivery strategies, while less PT antigens were needed using MN patches. The cytokines studies illustrated that PT vaccine MNs could elicit immune responses through multiple pathways, especially of Th1 and Th17 pathways. By integrating the above results, we concluded that the PT MN transdermal drug delivery system could improve antigen utilization and induce rapid and robust PT-specific immune responses, which possessed the superiority over the traditional s.c. injection.