Hermanson G, Whitlow V, Parker S, Tonsky K, Rusalov D, Ferrari M, Lalor P, Komai M, Mere R, Bell M, Brenneman K, Mateczun A, Evans T, Kaslow D, Galloway D, Hobart P
Vical Inc., San Diego, CA 92121, USA.
Proc Natl Acad Sci U S A. 2004 Sep 14;101(37):13601-6. doi: 10.1073/pnas.0405557101. Epub 2004 Sep 1.
DNA vaccines provide an attractive technology platform against bioterrorism agents due to their safety record in humans and ease of construction, testing, and manufacture. We have designed monovalent and bivalent anthrax plasmid DNA (pDNA) vaccines encoding genetically detoxified protective antigen (PA) and lethal factor (LF) proteins and tested their immunogenicity and ability to protect rabbits from an aerosolized inhalation spore challenge. Immune responses after two or three injections of cationic lipid-formulated PA, PA plus LF, or LF pDNAs were at least equivalent to two doses of anthrax vaccine adsorbed (AVA). High titers of anti-PA, anti-LF, and neutralizing antibody to lethal toxin (Letx) were achieved in all rabbits. Eight or nine animals in each group were challenged with 100x LD(50) of aerosolized anthrax spores 5 or 9 weeks after vaccination. An additional 10 animals vaccinated with PA pDNA were challenged >7 months postvaccination. All animals receiving PA or PA plus LF pDNA vaccines were protected. In addition, 5 of 9 animals receiving LF pDNA survived, and the time to death was significantly delayed in the others. Groups receiving three immunizations with PA or PA plus LF pDNA showed no increase in anti-PA, anti-LF, or Letx neutralizing antibody titers postchallenge, suggesting little or no spore germination. In contrast, titer increases were seen in AVA animals, and in surviving animals vaccinated with LF pDNA alone. Preclinical evaluation of this cationic lipid-formulated bivalent PA and LF vaccine is complete, and the vaccine has received U.S. Food and Drug Administration Investigational New Drug allowance.
由于DNA疫苗在人体中的安全记录以及其易于构建、测试和生产的特点，它们为抗生物恐怖主义制剂提供了一个有吸引力的技术平台。我们设计了编码基因解毒的保护性抗原（PA）和致死因子（LF）蛋白的单价和双价炭疽质粒DNA（pDNA）疫苗，并测试了它们的免疫原性以及保护兔子免受雾化吸入孢子攻击的能力。两次或三次注射阳离子脂质配方的PA、PA加LF或LF pDNA后的免疫反应至少相当于两剂吸附型炭疽疫苗（AVA）。所有兔子都产生了高滴度的抗PA、抗LF和针对致死毒素（Letx）的中和抗体。每组8或9只动物在接种疫苗5或9周后接受100倍半数致死剂量（LD50）的雾化炭疽孢子攻击。另外10只接种PA pDNA的动物在接种疫苗7个月后接受攻击。所有接受PA或PA加LF pDNA疫苗的动物都得到了保护。此外，接受LF pDNA的9只动物中有5只存活，其他动物的死亡时间也显著延迟。接受三次PA或PA加LF pDNA免疫的组在攻击后抗PA、抗LF或Letx中和抗体滴度没有增加，这表明几乎没有孢子萌发。相比之下，AVA组动物以及仅接种LF pDNA的存活动物的抗体滴度有所增加。这种阳离子脂质配方的双价PA和LF疫苗的临床前评估已经完成，该疫苗已获得美国食品药品监督管理局的研究性新药许可。
