Hollow microneedle-mediated intradermal delivery of model vaccine antigen-loaded PLGA nanoparticles elicits protective T cell-mediated immunity to an intracellular bacterium.

The skin is an attractive organ for immunization due to the presence of a large number of epidermal and dermal antigen-presenting cells. Hollow microneedles allow for precise and non-invasive intradermal delivery of vaccines. In this study, ovalbumin (OVA)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles with and without TLR3 agonist poly(I:C) were prepared and administered intradermally by hollow microneedles. The capacity of the PLGA nanoparticles to induce a cytotoxic T cell response, contributing to protection against intracellular pathogens, was examined. We show that a single injection of OVA-loaded PLGA nanoparticles, compared to soluble OVA, primed both adoptively transferred antigen-specific naïve transgenic CD8