Skin dendritic cells (DCs) such as Langerhans cells and dermal dendritic cells have a pivotal role in inducing antigen-specific immunity; therefore, transcutaneous cancer vaccines are a promising strategy to prophylactically prevent the onset of a variety of diseases, including cancers. The largest obstacle to delivering antigen to these skin DC subsets is the barrier function of the stratum corneum. Although reverse micellar carriers are commonly used to enhance skin permeability to hydrophilic drugs, the transcutaneous delivery of antigen, proteins, or peptides has not been achieved to date because of the large molecular weight of drugs. To achieve effective antigen delivery to skin DCs, we developed a novel strategy using a surfactant as a skin permeation enhancer in a reverse micellar carrier. In this study, glyceryl monooleate (MO) was chosen as a skin permeation enhancer, and the MO-based reverse micellar carrier enabled the successful delivery of antigen to Langerhans cells and dermal dendritic cells. Moreover, transcutaneous vaccination with the MO-based reverse micellar carrier significantly inhibited tumor growth, indicating that it is a promising vaccine platform against tumors.
Keywords: TRP-2 peptide; cancer immunotherapy; melanoma; reverse micelle; skin permeation enhancer; transcutaneous vaccine.