All four of its former patients agreed to take part in the program, said Rafi Ahmed, director of the Emory Vaccine Center, who is leading the effort.

Ahmed and colleagues intend to isolate antibodies made by these patients in response to the Ebola virus, and through a series of experiments in animals, identify the most effective ones for fighting off an Ebola infection.

The approach is unrelated to an experimental treatment provided to several Ebola patients in the United States, which involved transfusions of blood plasma from Ebola survivors.

Researchers will take two approaches. In one, they will produce large quantities of Ebola-fighting antibodies that could be infused into patients intravenously, a conventional approach known as passive immunization.

Protection using this method has a short half life of about two to three weeks, and the antibodies require refrigeration, which is not always available in countries fighting an infectious disease outbreak.

That is why the team is also testing the new method for making protective drugs based on DNA or RNA, rather than the older vaccine technology using killed or weakened viruses to stimulate an immune response, a process that can take several months to manufacture.

"In this method, we are trying to go in as silently as possible," bypassing the immune response, which may not always work, and directly providing the recipe for a highly effective antibody, said Col. Daniel Wattendorf, program director at DARPA who came up with the new strategy.