The antibodies from a survivor of Ebola, a key to future vaccine

L'anticorps d'un survivant d'Ebola, clé d'un futur vaccin

Researchers have identified a neutralizing antibody to the three strains of the Ebola virus that affects humans, an important discovery in the quest for a universal vaccine against this highly fatal disease, according to a study published Monday.

This antibody has been found in a survivor of the most severe Ebola outbreak to date, which has resulted in more than 11,000 deaths in West Africa between 2013 and 2016.

On the occasion of this epidemic, an experimental vaccine has been developed. A test of large extent led by WHO in Guinea in 2015 showed that he was very protective, but only against one of the strains of the virus.

This same vaccine is currently being used in a targeted vaccination campaign in the democratic Republic of the Congo (DRC), a country afflicted by a new epidemic which has already killed at least 500 people dead.

The antibody discovered by us researchers could go further in developing an effective vaccine against the three strains of Ebola that affect humans (the other two strains do not transmit the disease to non-human primates), explains an article published in the journal Nature Structural and Molecular Biology.

According to Kartik Chandran, a professor of immunology at the Albert Einstein College of Medicine in New York, his team managed to identify “the Achilles heel” of the virus.

By analyzing this antibody, already known to neutralize two strains of Ebola, the researchers were able to show that he could get around the defenses of the third strain of the virus.

“The molecular structure reveals that the antibody reaches a concealed pocket, flush” of the virus, told AFP Erica Ollmann Saphire, of the La Jolla Institute for Immunology, California.

Using this strategy, which overcomes the lures set up by the virus, “the antibody can aim effectively for a target that is common to all the varieties of the Ebola virus”, she added.

The Ebola virus spreads through the slightest contact with the bodily fluids of the sick or recently deceased. Responsible for high fevers, and hemorrhages, it is fatal in 30% to 90% of the cases according to the outbreaks and the virus type.