Previous studies have shown that Ebola virus has several weak points in its structure where antibodies can target and neutralise the virus.
Scientists have identified a new group of powerful antibodies to fight the Ebola virus isolated from the blood of a survivor of the 2014 outbreak, which could lead to the development of a vaccine against the deadly disease.
"Within weeks of receiving a blood sample from a survivor of the 2014 Ebola outbreak, we were able to isolate and characterise over 300 monoclonal antibodies that reacted with the Ebola virus surface glycoprotein," said Laura Walker, a senior scientist at a US-based biotechnology company Adimab, LLC, and a former student of The Scripps Research Institute (TSRI) in California.
Previous studies have shown that Ebola virus has several weak points in its structure where antibodies can target and neutralise the virus. However, the immune system typically needs a long period of trial and error to produce the right antibodies against these sites, so researchers have been working with only a small library of anti-Ebola options.
"These types of antibodies could be developed into different types of antibody cocktails or therapeutics, in addition to advancing vaccine design," said Andrew Ward, professor at TSRI. Researchers at TSRI and the US Army Medical Research Institute of Infectious Diseases (USAMRIID) identified more than 300 antibodies that reacted with the Ebola virus surface glycoprotein - the viral structure that fuses with host cells.
They performed an in-depth analysis of the therapeutic potential of these antibodies and developed antigens - molecules that can "fish" for antibodies in blood serum. About 77% of the antibodies in the study showed the potential to neutralise Ebola virus, and several antibodies demonstrated significant protection against the virus in mouse models.
"We identified three highly protective antibodies that each targeted a different site - or epitope - on the Ebola virus glycoprotein," said first author Zachary Bornholdt, an assistant professor at TSRI. Since these are human antibodies, not modified mouse antibodies, researchers potentially could quickly use them to design a treatment.
Furthermore, with these new antibodies available, researchers might be able to design secondary treatments in case the Ebola virus mutates to escape other treatments. The researchers used an imaging technique, called electron microscopy, to investigate exactly where the antibodies were binding with Ebola virus.
The imaging showed a previously unknown Achilles heel on the virus - a spot at the base of the Ebola virus surface glycoprotein. While Ebola virus mutates rapidly, this site is part of the virus's larger machinery and tends to stay the same. This means targeting this spot could neutralise many strains of Ebola.
The study was published in the journal Science.
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 "This image shows a key Ebola virus protein and vulnerable sites where antibodies (in colour) can bind and neutralise it.")
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