Massachusetts General Hospital, USA
Xinyuan Chen has completed his PhD from Nanjing University and Postdoctoral studies from Massachusetts General Hospital/Harvard Medical School, USA. He is now Assistant Professor at University of Rhode Island, USA. He has published 17 papers in reputed journals and is a recipient of NIH Career Development Award.
Skin vaccination attracted much attention in the last two decades due to significantly improved vaccine immunogenicity as compared to conventional intramuscular vaccination. Yet, the technical difficulty and frequent local reactions hamper its broad application in the clinic. We developed a micro-fractional epidermal powder delivery (EPD) technology to facilitate skin vaccination and minimize local reactions. EPD is based on ablative fractional laser or microneedle treatment to generate microchannel (MC) arrays in the epidermis followed by topical application of powder drug/vaccine-coated array patches to deliver drug/vaccine into the skin. EPD could deliver more than 80% sulforhodamine b (SRB) and model antigen ovalbumin (OVA) into murine, swine, and human skin within 1 h. EPD of OVA induced a comparable anti- OVA antibody titer to intradermal (ID) injection and much higher anti-OVA antibody titer than tape stripping-based patch delivery. Strikingly, the micro-fractional delivery significantly reduced local side effects of LPS/CpG adjuvant and BCG vaccine and resulted in complete skin recovery. In contrast, ID injection induced severe local reactions that persisted for weeks without complete skin recovery. While reducing local reactogenicity, EPD of OVA/LPS/CpG and BCG vaccine induced a comparable humoral immune response to ID injection. EPD of vaccinia virus encoding OVA induced significantly higher and long-lasting interferon γ-secreting CD8+ T cellsthan ID injection. In conclusion, EPD represents a promising technology for needle-free, painless skin vaccination with reduced local reactogenicity and at least sustained immunogenicity.