Study of Japanese encephalitis virus DNA vaccine using the transcutaneous immunization

• Main Authors: Jing-Yan Cheng, 程景彥
• Other Authors: Chang-Jer Wu
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/12760664195927601741

碩士 === 國立臺灣海洋大學 === 食品科學系 === 95 === Needles and syringes are the most commonly used methods for administering vaccines. Needle-based immunizations have several limitations including unsafe injection practices, reused by health-care provides infections and needle phobia. Skin is the biggest organ of human that makes cutaneous immunization easy to operate. The epidermis of skin contains the antigen presenting cells and Langerhans cells (LC) , which can modulate the immune responses. The new vaccine technology, DNA vaccine, can induce both cell-mediated and humoral immune responses to prevent the infectious diseases. In order to ensure the outcome of therapy, the efficiency of gene delivery is very important. We used cationic liposome –DOTAP and DC-Chol/DOPE as vehicle for transdermal delivery. In vitro transfection efficiency of plasmid DNA/liposome was assessed by the expression of a green fluorescent protein (GFP) in BHK-21 cells. The optimal ratio of both liposomes to DNA for maximal transfection efficiency was 5:1 (w/w). The same formulation was tested for in vivo transfection efficiency and non-invasively applying the lipoplex (DNA/liposome complexes) on hair-removed dorsal skin of mice. It was found that genes were transported into epidermal and lymph node in 3 days once applied on intact skin. In immunization studies, C3H/HeN mice were given three gene gun shots of 1 μg or liposome-entrapped 50 μg pCJ3/ME (a expression vector that contains the gene of JEV membrane protein and envelope protein) , and bled for 2 weeks intervals. After being inoculated three times, mice were immuned from challenging with 50 times the 50% lethal dose (LD50) of JEV (Beijing-1 strain). This simple, noninvasive technique by using cationic liposome to delivery DNA provides an efficient delivery route for gene therapy and drug delivery to the dermal organ site.