Scientists have successfully isolated human antibodies from Ebola survivors that can neutralise multiple species of the deadly virus, and may be a “silver bullet” against the disease that has killed over 11,000 people in West Africa in the past two years.
“This work suggests there are common elements across different groups of Ebola viruses,” said James Crowe Jr, from the Vanderbilt University Medical Centre in US.
“Maybe we can come up with one therapeutic or one vaccine that would solve all of them,” he said.
“A remarkably diverse array of virus-specific antibodies was isolated, which appeared to bind to various parts of the envelope protein of the virus,” said Alexander Bukreyev, a professor at the University of Texas Medical Branch in Galveston (UTMB) in US.
“Some of the antibodies neutralised not only Ebola Bundibugyo virus, but also Ebola Sudan virus and Ebola Zaire virus, similar to that which caused the recent outbreak in West Africa,” Bukreyev said.
Ebola virus disease is spread by contact with contaminated body fluids, including blood and semen. It can cause massive bleeding. The death rate is about 50 per cent.
Several experimental Ebola vaccines and monoclonal antibody therapies currently are in development.
Monoclonal antibodies are generated by clones of a type of white blood cell that have been fused to myeloma (cancer) cells to form fast-growing “hybridomas”.
Like heat-seeking missiles, they seek out and destroy their targets, in this case, the Ebola virus.
Unlike vaccines, antibody treatments are meant to provide short-term protection to health care workers and others at risk of exposure.
They also could be used as antiviral drugs to treat patients who are already infected with Ebola virus.
Previous research has found that ‘bispecific’ monoclonal antibodies they engineered to recognise two species of Ebola virus provided a high degree of protection in mice exposed to two Ebola viral species.
In this study, researchers used a high-efficiency method they developed to quickly isolate and generate large quantities of monoclonal human antibodies from the blood of survivors of a 2007 outbreak in Uganda who were infected by the Bundibugyo ebolavirus.
In addition to neutralising multiple Ebolavirus species, one of the antibodies also protected guinea pigs from a lethal challenge of virus.
“This work points the way to using fully human antibodies as the next generation of antibody therapeutics,” Crowe said.
The study was published in the journal Cell.