L13.    Follicular targeting – implementation in transcutaneous vaccination.
Annika Vogt, Behazine Combadiere, Brice Mahe, Sabrina Hadam, Karola Stieler, juergen Lademann, Hans Schaefer, Brigitte autran, Wolfram Sterry, Ulrike Blume-Peytavi; Clinical Research Center for Hair and Skin Physiology, Department of Dermatology and Allergy, Charite-Universitätsmedizin Berlin, Germany.

Due to the unique role of the hair follicle in percutaneous penetration, drug delivery systems, which target active compounds to the hair follicle, may result in a better penetration and a higher efficiency of hair and skin therapy (“Follicular Targeting”). Applications in immunotherapy, e.g. transcutaneous vaccination, are of particular interest, because skin antigen-presenting cells (APCs) can be found at particularly high densities in hair follicle-bearing skin, where they are concentrated around the upper portion of the hair follicles. Our in vitro studies on human skin revealed, that nanoparticles, due to their ability to aggregate in the hair follicle openings and to penetrate along the follicular duct, are promising carrier systems for transfollicular drug delivery. Transcutaneously applied nanoparticles in the size range of 40nm, moreover, were capable of penetrating the epithelium and entered epidermal LCs, suggesting that such particles may be used to transcutaneously deliver active vaccine compounds, via the hair follicle, into cutaneous APCs. To further assess the potential of particle-based vaccines in transcutaneous vaccination, we developed a standard operating procedure (SOP) for transcutaneous vaccine delivery based on our current knowledge on follicular penetration. In a limited number of volunteers, we found that this newly developed SOP is safe and efficient at inducing immune responses.