Transdermal Patch for Co–delivery of an Antigen and Dendritic Cell–Targeting Peptide to Enhance Immunization

Abstract

Transdermal immunization is an efficient strategy which offers a promising needle–free alternative to conventional injectable vaccines. However, effective antigen delivery across the skin remains a major challenge due to the presence of the stratum corneum as a barrier. In this study, we report a transdermal patch formulation by using a solid– in–oil (S/O) nanodispersion of ovalbumin (OVA) and a dendritic cell (DC) targeting peptide (HR8) within a pressure sensitive adhesive matrix to enhance immune responses. S/O nanodispersions were prepared using different OVA and HR8 molar ratios and were characterized in terms of particle size and OVA release behavior. Three of them exhibited particle sizes < 500 nm and demonstrated sustained OVA release in vitro. In vivo immunization studies in C57BL/6N mice exhibited that HR8 enhanced OVA–specific immune responses in a concentration dependent manner. The formulations containing OVA and HR8 at a molar ratio of 1 : 3 exhibited approximately five–fold higher OVA–specific immune responses than the corresponding S/O formulation without HR8 peptide. These findings suggest the feasibility of transdermal co–delivery of an antigen and a DC targeting peptide using an S/O patch system as a safe, non–invasive platform for the enhancement of vaccine induced immunity.