Ebola virus disarmed by excising a single geneJanuary 22, 2008MADISON - The deadly Ebola virus, an emerging public health concern in Africa and a potential biological weapon, ranks among the most feared of exotic pathogens. Due to its virulent nature, and because no vaccines or treatments are available, scientists studying the agent have had to work under the most stringent biocontainment protocols, limiting research to a few highly specialized labs and hampering the ability of scientists to develop countermeasures. Now, however, a team of researchers from the University of Wisconsin-Madison has figured out a way to genetically disarm the virus, effectively confining it to a set of specialized cells and making the agent safe to study under conditions far less stringent than those currently imposed.
"We wanted to make biologically contained Ebola virus," explains Yoshihiro Kawaoka, a professor of pathobiological sciences in the UW-Madison School of Veterinary Medicine and the senior author of a paper describing the system for containing the virus published today (Jan. 21, 2008) in the Proceedings of the National Academy of Sciences. "This is a great system." The Ebola virus first emerged in 1976 with outbreaks in Sudan and Zaire. There are several strains of the virus, which causes hemorrhagic fever and during outbreaks kills anywhere from 50-90 percent of its human victims. At present, research on live Ebola virus is confined to the very highest level of biosafety, known as Biosafety Level 4 (BSL 4). Because such laboratories are rare, small and very expensive, basic research that is the basis for any potential drugs or vaccines to thwart the virus has been limited to perhaps half a dozen labs worldwide. The system devised by Kawaoka and his colleagues could provide a way to greatly expand studies of the pathogen and speed the development of countermeasures. Taming Ebola virus, according to the new study, depends on a single gene known as VP30. Like most viruses, Ebola is a genetic pauper. It has only eight genes and depends on host cells to provide much of the molecular machinery to make it a successful pathogen. The virus's VP30 gene makes a protein that enables it to replicate in host cells. Without the protein, the virus cannot grow. "The altered virus does not grow in any normal cells," says Kawaoka. "We made cells that express the VP30 protein and the virus can grow in those cells because the missing protein is provided by the cell." It took years, Kawaoka explains, to find which viral protein was not toxic to cells and could thus be used to develop a system, using monkey kidney cells, to confine the virus. And Kawaoka, an internationally noted virologist, is convinced of the safety of the new system: "We did this work in a BSL 4, and the altered cells didn't produce any infectious virus after many passages or replication cycles." With the exception that it is unable to grow in anything but cells engineered to express the VP30 protein, the virus is identical to the pathogen found in the wild, making it ideal for studies of basic biology, vaccine development and screening for antiviral compounds. "This system can be used for drug screening and for vaccine production," Kawaoka says, noting that getting the equipment and compounds for such work into a BSL 4 lab is extremely difficult. "High throughput screening (for drugs) in a BSL 4 is almost impossible." Currently, live Ebola virus can be studied only in a BSL 4 laboratory. Any proposal to permit studying the pathogen in lower safety level labs is certain to generate controversy. But according to Kawaoka, making the agent available for study to a broader cross section of science is essential for thwarting the virus that kills a high percentage of its victims because there is now no defense against it. A new strain of Ebola, which so far has emerged only in remote areas of the world, was recently identified in Uganda and has killed at least 40 people. "This is an emerging virus and it's highly lethal," Kawaoka says. "But because of the BSL 4 requirement, knowledge of this virus is limited." University of Wisconsin-Madison | |||||||||||||||||||||
|
Related Ebola Current Events and Ebola News Articles UT Southwestern researchers develop new strategy for broad spectrum anti-viral drugs Bavituximab, an anti-viral drug developed by UT Southwestern Medical Center researchers, shows promise as a new strategy to fight viral diseases, including potential bioterrorism agents. Scientists discover new species of Ebola virus Scientists report the discovery of a new species of Ebola virus, provisionally named Bundibugyo ebolavirus, November 21 in the open-access journal PLoS Pathogens. First Holistic Guide to Primate Disease Covers Critical Gap in Global Health Why are so many infectious diseases jumping from animals to humans? Why do we have so little capacity to predict epidemics, or avoid them? 'Deadly dozen' reports diseases worsened by climate change Health experts from the Wildlife Conservation Society today released a report that lists 12 pathogens that could spread into new regions as a result of climate change, with potential impacts to both human and wildlife health and global economies. Scientists uncover Ebola cell-invasion strategy University of Texas Medical Branch at Galveston researchers have discovered a key biochemical link in the process by which the Ebola Zaire virus infects cells - a critical step to finding a way to treat the deadly disease produced by the virus. Wildlife Conservation Society discovers 'Planet of the Apes' The world's population of critically endangered western lowland gorillas received a huge boost today when the Wildlife Conservation Society released a census showing massive numbers of these secretive great apes alive and well in the Republic of Congo. Scripps research scientists reveal key structure from ebola virus Described in the July 10, 2008 issue of the journal Nature, the research reveals the shape of the Ebola virus spike protein, which is necessary for viral entry into human cells, bound to an immune system antibody acting to neutralize the virus. Vaccine for Ebola virus One of the world's deadliest diseases, caused by the Ebola virus, may finally be preventable thanks to US and Canadian researchers, who have successfully tested several Ebola vaccines in primates and are now looking to adapt them for human use. Penn scientists find a protein that inhibits Ebola from reaching out to infect neighboring cells Scientists at the University of Pennsylvania School of Veterinary Medicine have identified a protein, ISG15, that inhibits the Ebola virus from budding, the process by which viruses escape from cells and spread to infect neighboring cells. Scripps scientists studying sepsis in mice find potential drug targets for deadly disease "We have identified a key connection of signaling pathways in the cascade of events leading to sepsis. This defines a crucial point where the immune system spirals out of control to cause severe sepsis and where there is an opportunity for therapeutic intervention," says Scripps Research Professor Wolfram Ruf, who led the research with his postdoctoral fellow Frank Niessen. More Ebola Current Events and Ebola News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||