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 Traditional vaccines boost the immune system’s response to
infections. The new project will inject people with genetic
material, such as DNA or RNA, in hopes of spurring a person’s own
cells to make specific antibodies capable of fighting Ebola or other
pathogens.
"The person's body is the factory," said Dr. James Crowe of
Vanderbilt University, one of the collaborators on the project.
"It's a cool idea."
Experts say the method, if proven to be safe and effective, would be
faster and cheaper than conventional drug production and could
potentially be used to treat illnesses such as seasonal flu or
malaria.
Antibodies are typically grown in large vats of mammal cells or in
some cases, tobacco plants, such as Mapp Biopharmaceutical's
experimental Ebola treatment ZMapp.
The Defense Advanced Research Projects Agency (DARPA), the
Pentagon's elite research arm, has awarded Emory up to $10.8 million
over three years to direct the project.
It will include research teams at the U.S. Centers for Disease
Control and Prevention, the U.S. Army Medical Research Institute of
Infectious Diseases (USAMRIID), and several academic research labs
including the University of Wisconsin-Madison, Rockefeller
University, Vanderbilt and Scripps Research Institute.
Getting access to blood samples from survivors of the current Ebola
outbreak in West Africa has been challenging, but Emory has a
distinct advantage in having treated a small number of patients on
U.S. soil.
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.
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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.
Wattendorf said the effort is based on prior, early stage research
with drugmakers Novartis and Sanofi looking at whether they could
make vaccines out of ribonucleic acid, or RNA.
"What was particularly intriguing about RNA was that it has no
chance of integrating into the human genome," he said. The effect
was temporary.
Initially, the technology was being developed in hopes of protecting
soldiers from seasonal flu or germs that cause diarrhea on the
battlefield, but the Ebola outbreak presented an opportunity to
accelerate the research.
To succeed, researchers will need to identify an effective delivery
system to carry the genetic instructions into the body and learn how
to quickly identify the most protective antibodies. The goal is to
get the process down to 90 days for most diseases, Wattendorf said.
The group is in the process of characterizing several Ebola antibody
candidates to find which are the most potent, Ahmed said. At that
point, the researchers and DARPA will seek out drug company
partners.
Testing in people could begin within two years, with the goal of
having a better weapon for the next Ebola outbreak.
(Reporting by Julie Steenhuysen; Editing by Michele Gershberg and
Sue Horton)
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