Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Plants provide accurate low-cost alternative for diagnosis of West Nile Virus

25.10.2012
While the United States has largely been spared the scourge of mosquito-borne diseases endemic to the developing world—including yellow fever, malaria and dengue fever—mosquito-related illnesses in the US are on the rise. One pathogen of increasing concern in the U.S. is an arbovirus known as West Nile.

Now Qiang “Shawn” Chen, a researcher at Arizona State University’s Biodesign Institute and a professor in the College of Technology and Innovation has developed a new method of testing for West Nile, using plants to produce biological reagents for detection and diagnosis.

The new research, conducted by Chen and his colleagues at the Center for Infectious Diseases and Vaccinology recently appeared in the Journal of Biomedicine and Biotechnology.

“One critical issue in WNV diagnosis concerns the difficulty of distinguishing WNV infection from other closely related diseases, such as St. Louis encephalitis and dengue fever, due to the cross-reactivity of antibodies among flaviviruses,” Chen says. “It is important to develop better diagnostic tools with enhanced accuracy for both treatment and diagnostic purposes.”

Thus far, the 2012 outbreak of West Nile in the United States is on track to be one of the worst on record. According to the Center for Disease Control, 48 states have reported West Nile virus infections in people, birds, or mosquitoes as of October 9th of this year.

To date, 4,249 cases of West Nile virus disease have been reported in humans, including 168 deaths. Of these cases 2,123 (50 percent) appeared in the more severe or neuroinvasive form of the disease, causing meningitis and encephalitis, while 2,126 cases were classified as non-neuroinvasive.

These figures represent the highest number of West Nile cases reported to the CDC since 2003, with nearly 70 percent reported from eight states: Texas, California, Louisiana, Mississippi, South Dakota, Michigan, Oklahoma, and Illinois. Over a third of total cases have been reported from Texas.

The alarming upswing in West Nile cases coupled with their broad geographic distribution demand new techniques for both diagnosis and treatment. Chen and his colleagues have been exploiting the power of plant biotechnology to achieve these goals.

Earlier, Chen’s group developed the first successful plant-derived therapeutic to combat West Nile post-infection, reporting their results in the Proceedings of the National Academy of Science. The current study advances efforts to create a diagnostic test for West Nile that will overcome barriers of existing methods, including limited accuracy, prohibitive cost and scalability.

In nearly all cases, West Nile is transmitted to humans through the bite of an infected mosquito. Mosquitoes acquire the virus after feeding on infected birds. The virus then migrates to the mosquito's salivary glands, from which it may be injected into humans and animals. There, it can multiply and produce characteristic symptoms of West Nile disease. These may present as flu-like malaise including fever and chills, headaches, fatigue and pain in muscles and joints. Symptoms typically last three to six days, but may persist for weeks.

In around 1 in 150 WNV cases, individuals develop infections of the brain (encephalitis) or surrounding tissue (meningitis), often producing severe headache, fever, stiffness, confusion, convulsions, coma, tremors, muscle weakness and paralysis. Those with neurologic involvement may require weeks of hospitalization and may suffer permanent health effects including muscle weakness and paralysis. Around 10 percent of people with WNV encephalitis die.

Faced with the growing threat of mosquito-borne epidemics, researchers like Chen stress the necessity of developing rapid, low-cost platforms for diagnosis of West Nile. Traditionally, cell cultures from serum, cerebrospinal fluid or tissues have been examined but the short viremic phase and low viral count of WNV in blood and spinal fluid limit the sensitivity and accuracy of such tests. Protein-based methods like ELISA have become standard tests for West Nile, yielding better results but at considerably higher cost and with limited scalability.

In the current study, plants were exploited for their ability to produce large volumes of proteins that can be used for diagnostic testing. As Chen explains, proteins produced in this way traditionally require a lengthy time period before transgenic plant lines can be established. By contrast, the new method, which makes use of plant viral-based vectors like Tobacco Mozaic Virus and Gemini Virus, relies on the ability of plants to transiently express particular target genes, yielding the desired protein in 1-2 weeks.

The technique provides the speed and flexibility of a bacterial gene expression system while permitting the posttranslational modifications of proteins afforded by mammalian cell culture approaches.

Chen’s group used plant transient expression systems to produce two varieties of protein reagents useful for the detection and diagnosis of WNV—one a recombinant antigen and one a monoclonal antibody. High expression levels of both reagents were observed in two kinds of plants: Nicotiana benthamiana (a close relative of tobacco) and lettuce. The two reagents may be readily purified to greater than 95 percent and retain their native functionality and specificity.

The production of plant-derived antigens and monoclonal antibodies offers an attractive alternative to the use of mammalian, insect or bacterial cell cultures and demonstrates the capability of plants to provide accurate and flexible diagnostic reagents not only for WNV but a broad range of arboviruses affecting human health.

“Our test will improve the accuracy of diagnosis, leading to the proper treatment of patients affected by WNV,” Chen says. “The plant-derived monoclonal antibody we examined is not only low-cost, but highly specific for WNV antigen and does not recognize antigens from other flaviviruses.” Chen further notes that application of this research will ultimately allow a broad range of WNV surveillance capabilities, from clinical diagnosis to global distribution patterns in wild bird and mosquito populations.

Click to read the study
http://www.hindawi.com/journals/jbb/2012/106783/

Richard.Harth | EurekAlert!
Further information:
http://www.asu.edu
http://www.biodesign.asu.edu/news/plants-provide-accurate-low-cost-alternative-for-diagnosis-of-west-nile-virus

More articles from Life Sciences:

nachricht Building a brain, cell by cell: Researchers make a mini neuron network (of two)
23.05.2018 | Institute of Industrial Science, The University of Tokyo

nachricht Research reveals how order first appears in liquid crystals
23.05.2018 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Building a brain, cell by cell: Researchers make a mini neuron network (of two)

23.05.2018 | Life Sciences

One-way roads for spin currents

23.05.2018 | Physics and Astronomy

A simple mechanism could have been decisive for the development of life

23.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>