Chichester Jessica A, Manceva Slobodanka D, Rhee Amy, Coffin Megan V, Musiychuk Konstantin, Mett Vadim, Shamloul Moneim, Norikane Joey, Streatfield Stephen J, Yusibov Vidadi
1Fraunhofer USA Center for Molecular Biotechnology; Newark, DE USA.
Hum Vaccin Immunother. 2013 Mar;9(3):544-52. doi: 10.4161/hv.23233. Epub 2013 Jan 16.
The potential use of Bacillus anthracis as a bioterrorism weapon threatens the security of populations globally, requiring the immediate availability of safe, efficient and easily delivered anthrax vaccine for mass vaccination. Extensive research efforts have been directed toward the development of recombinant subunit vaccines based on protective antigen (PA), the principal virulence factor of B. anthracis. Among the emerging technologies for the production of these vaccine antigens is our launch vector-based plant transient expression system. Using this system, we have successfully engineered, expressed, purified and characterized full-length PA (pp-PA83) in Nicotiana benthamiana plants using agroinfiltration. This plant-produced antigen elicited high toxin neutralizing antibody titers in mice and rabbits after two vaccine administrations with Alhydrogel. In addition, immunization with this vaccine candidate protected 100% of rabbits from a lethal aerosolized B. anthracis challenge. The vaccine effects were dose-dependent and required the presence of Alhydrogel adjuvant. In addition, the vaccine antigen formulated with Alhydrogel was stable and retained immunogenicity after two-week storage at 4°C, the conditions intended for clinical use. These results support the testing of this vaccine candidate in human volunteers and the utility of our plant expression system for the production of a recombinant anthrax vaccine.
炭疽芽孢杆菌作为生物恐怖主义武器的潜在用途威胁着全球民众的安全，这就需要立即提供安全、高效且易于递送的炭疽疫苗用于大规模接种。大量研究工作致力于基于保护性抗原（PA）开发重组亚单位疫苗，PA是炭疽芽孢杆菌的主要毒力因子。在生产这些疫苗抗原的新兴技术中，我们的基于启动载体的植物瞬时表达系统是其中之一。利用该系统，我们通过农杆菌浸润法在本氏烟草植株中成功构建、表达、纯化并鉴定了全长PA（pp-PA83）。这种植物生产的抗原在使用氢氧化铝佐剂进行两次疫苗接种后，在小鼠和兔子体内引发了高毒素中和抗体滴度。此外，用这种候选疫苗免疫可使100%的兔子免受致命的雾化炭疽芽孢杆菌攻击。疫苗效果呈剂量依赖性，且需要氢氧化铝佐剂的存在。此外，用氢氧化铝配制的疫苗抗原在4°C下储存两周后稳定且保留免疫原性，这是临床使用的预期条件。这些结果支持在人类志愿者中测试这种候选疫苗，以及我们的植物表达系统用于生产重组炭疽疫苗的实用性。
