The so-called broadly neutralizing antibodies were discovered in the blood of a survivor of the West African epidemic, which ran from late 2013 to mid-2016. The deadly virus killed more than 11,000 people of the nearly 29,000 who became infected in Liberia, Guinea and Sierra Leone.
Ebola got its name from the first documented outbreak, which occurred along the Ebola River in the Democratic Republic of the Congo, formerly Zaire, in 1976. Since then, there have been two dozen outbreaks of Ebola in Africa, including a current one that has infected nine people in the DRC. Three people have died.
Kartik Chandran, a professor in the Department of Microbiology and Immunology at the Albert Einstein College of Medicine in Bronx, New York, helped identify the antibodies, which were described online in the journal Cell. He is optimistic that the antibodies can be used as a single therapy to treat all Ebola viruses.
'Based on the nonhuman primate studies that are ongoing, and given the fact that they are pretty predictive, I would be optimistic that they could be used to protect people and reverse disease,' Chandran said.
350 antibodies isolated
Researchers isolated about 350 antibodies from the human blood sample, two of which showed promise in neutralizing three viruses in tissue culture. The antibodies work by interfering with a process that the pathogen uses to infect and multiply inside cells.
The drug company Mapp Pharmaceutical Inc. is now testing the antibodies in monkeys to make sure they are safe and effective.
A forerunner of the experimental drug, called Zmapp, was in the experimental stages when it was pressed into service during the last epidemic. Zmapp is a combination of cloned antibodies discovered in mice that enlist the body's natural immune system to fight infection. If given up to five days after symptoms appear, it can cure the disease.
The problem, Chandran said, is Zmapp is not terribly specific and works to neutralize only Ebola Zaire, one of the five known viruses. He said the broadly neutralizing human antibodies attack and destroy all of the viruses.
It took scientists just six months to discover the antibodies, according to Chandran, 'so this is really incredibly fast and incredibly gratifying. And we are hoping that things will continue at this pace and that in very short order we will be in a position to be able to test these things in people.'
While the broadly neutralizing antibodies are being developed as a treatment, Chandran envisions using them in a vaccine that can be given ahead of an Ebola outbreak to guard against infection.