Cutaneous DNA Immunization: Enhancing Penetration by Hair Follicle Modification or Microneedle Application

Vaccines are often administered by subcutaneous or intramuscular injections. However, there is evidence that the skin is an ideal site for vaccination. Delivery of antigens into the epidermis and dermis layers of skin, where there is a high density of LCs and DCs, can potentially induce a strong immune response. However, by nature, skin is not very permeable for antigens. The major hurdle in skin permeation is the outermost stratum corneum layer. Cutaneous DNA immunization was proven feasible in 1999. However, the immune response induced by cutaneous DNA immunization is generally weak, and various techniques have been explored to enhance it. In this chapter, we will discuss two of the techniques, cutaneous DNA immunization by modifying hair follicles or hair follicle cycle and microneedle-mediated cutaneous DNA immunization.