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Can Blood of Ebola Survivors Lead to Cure?
In an exclusive report, Reuters has described the ongoing search for effective treatments for the deadly Ebola virus, which has claimed more than 7,000 lives in West Africa.
For months, the report says, Vanderbilt University researcher Dr. James Crowe has been seeking access to the blood of U.S. Ebola survivors, hoping to extract the proteins that helped them overcome the infection for use in new, potent drugs.
His efforts finally paid off in mid-November with a donation from Dr. Rick Sacra, a University of Massachusetts physician who contracted Ebola while working in Liberia. The donation put Crowe at the forefront of a new model for fighting the virus.
Crowe is working with Mapp Biopharmaceutical Inc, which he said will manufacture the antibodies for further testing under a National Institutes of Health grant. Mapp is currently evaluating its own Ebola drug ZMapp, a cocktail of three antibodies that has shown promise in treating a handful of Ebola patients.
Crowe’s hope is to improve on ZMapp by isolating the human antibodies of actual survivors and to create a drug effective against all strains of Ebola.
Crowe, who directs the Vaccine Center at Vanderbilt, is working with Sacra’s B cells –– white blood cells that form antibodies. He and his colleagues will synthesize genes from the most potent of these antibodies, which can be made into treatments. Drugs created this way are called monoclonal antibodies, a manufactured protein that attacks a specific target, in this case a receptor on the Ebola virus.
The current version of ZMapp was developed in mouse blood cells that were exposed to samples containing Ebola virus fragments from a 1995 outbreak in the Democratic Republic of Congo. These cells were genetically modified to make them more human.
“They may or may not work. We don’t know that yet,” Crowe said of ZMapp. The next-generation product Crowe is working on will be fully human, using antibodies generated by Ebola survivors, making it less likely to cause adverse effects.
A key production issue for ZMapp has been its slow method of growing antibodies in the cells of tobacco plants. In October, Mapp started working with biotechnology company Amgen to mass-produce ZMapp antibodies in mammalian cells, a well-established manufacturing process.
Crowe said the antibodies he is working on would be produced in both cell lines and tobacco plants. Vanderbilt will license the most-promising drug candidates, and at least four commercial partners, including Mapp, are considering whether to license them.
Crowe estimates that clinical trials could begin in the late spring or early summer of 2015.
Source: Reuters; December 22, 2014.