Vaccines
Vaccination is one of the most important instruments
to fight infectious diseases. Topical vaccine
delivery is another future promising aspect
of nanotechnology.
The skin contains a tight network of immune
cells, particularly Langerhans cells and dendritic
cells with the ability to induce a specific
immune response. Topical vaccination could be
an efficient way to activate effector-T-cells and
induce an immune response (30, 31).
Hair follicles were shown to be a promising
target for transcutaneous vaccination (32), as
they are rich in immunecompetent cells in the
infundibular part of the root sheath and around
the excretory duct of the sebaceous gland. Hair
follicles offer a considerable penetration pathway
and potential intracutaneous reservoir for
topically applied substances which makes them
an important target for topical vaccination (32).
Jung et al. (33) reported a new methodology
to assess the strategy of topical vaccination
using nanosized liposomes. They suggested that
interfollicular penetration through the stratum
corneum seems to play a minor role for the
tested liposomes, whereas follicular penetration
of the liposomes seems to be the main route. In
detail, in this study it was found that liposomes
penetrate deeper into hair follicles than a standard
macromolecule formulation enhancing the
transfollicular drug uptake.
Vaccines made of pseudoviral nanoliposomes
and micelles containing plasmid DNA have
been shown to reach epidermal dendritic cell
precursors and Langerhans cells. Langerhans
cells then drain to regional lymph nodes, present
antigen to T cells, and elicit a potent cellmediated
immune response (34). This may be an
effective strategy for vaccines against cutaneous
and systemic infectious and neoplastic diseases.