A new therapeutic治疗的 made from tobacco plants has been shown to arrest逮捕，阻止 West Nile virus infection, according to a new study by Arizona State University scientist Qiang Chen and his colleagues. Chen, a researcher at Arizona State University's Biodesign Institute and professor in the PolyTechnic² Campus' College of Technology and Innovation, is the first to demonstrate a plant-derived³ treatment to successfully combat West Nile virus after exposure and infection. The research appears in this week's issue of the Proceedings⁴ of the National Academy of Sciences (advanced online edition).

There are currently no available vaccines疫苗 against West Nile, nor effective therapeutics for human use, so the current findings are a considerable advancement⁶ and may offer the best hope thus far迄今，现在为止 that the West Nile virus infection can be stopped, even several days after viral infection.

West Nile virus has made alarming inroads损害，侵犯 in North America, causing disease outbreaks throughout the U.S., as well as in areas of Canada, Mexico, the Caribbean and South America. Elderly individuals and those with depressed⁷ immunity⁸ are particularly vulnerable to易受……的攻击 West Nile, a mosquito-borne illness which can cause a potentially lethal致命的 inflammation of the brain.

Chen's group demonstrated the versatility用途广泛，多功能性 of plant-based biotechnology. "The goal of this research was twofold," said Chen. "First, we wanted to show proof-of- concept, demonstrating that plant-made antibodies抗体 can work as effective post-exposure therapeutics. Secondly¹¹, we've sought to develop a therapeutic¹ which can be made inexpensively so that the health care systems in developing countries can afford it."

Issues of affordability支付能力，负担能力 for such antibody-based treatments are central to the challenge, Chen stresses, with the costs for development of a traditional pharmaceutical¹³ mammalian哺乳类的 cell line production facility often running into the tens of millions of dollars. Besides being inexpensive, plants offer other advantages. Mammalian cell lines may run the risk of harboring animal pathogens病原体，致病菌 such as viruses or infectious protein agents known as prions朊病毒，小蛋白粒, not found in plants. Plants also allow production of pharmaceutical products to be easily scaled up to whatever quantities are required. "With mammalian cells systems, the physical size of the bioreactor生物反应器 is limiting," said Chen, "whereas with plants, we can just plant another acre英亩，土地."

The study examined antibodies against West Nile virus derived from mammalian cell lines and compared their effectiveness with those extracted from plants. The plants used to produce the antibodies are a relative of common tobacco, a member of the Solanceae family of plants, which produce abundant leaves for harvesting material and are also prolific¹⁴多产的，丰富的 seed producers. Seven days after the introduction of antibody genes¹⁵ into plants, the leaves are harvested, homogenized and purified to remove extraneous外来的 material.