New therapies could tackle Ebola
Scientists have isolated therapeutic antibodies from healthy volunteers exposed to the Ebola vaccine but not Ebola virus itself, suggesting that protective therapies could be developed from people who are disease-free.
The researchers, from the Medical Research Council (MRC) Human Immunology Unit at the University of Oxford, say their findings could apply to other infectious diseases including SARS (severe acute respiratory syndrome) and avian flu.
The current outbreak of the serious viral illness in Democratic Republic of Congo is spreading at its fastest rate yet, eight months after it was first detected, the World Health Organization said on Monday (1 April).
A worldwide effort to develop treatments has resulted in a handful of promising candidates, including antibody therapies to help treat those already infected, according to UK Research and Innovation’s MRC.
The MRC scientists considered whether blood samples taken from volunteers in vaccine trials could produce protective antibodies against Ebola. These samples are readily available from vaccine trial studies, though they have not until now been considered because of concerns that they may not have the same potential compared to antibodies taken from survivors’ blood.
Conventionally, antibodies intended for therapy are collected from individuals who have survived infection because the antibodies in their blood are seen as being more potent from prolonged exposure. However, blood samples from survivors can be difficult to obtain and may have risks, such as persistent viruses or other pathogens, tied to them.
The researchers isolated 82 antibodies taken from 11 healthy volunteers participating in an Ebola vaccine trial at the Jenner Institute in Oxford. Despite having less maturation time, the team noticed that one-third of all the antibodies isolated were effective at neutralising the Zaire species of Ebola, which is the basis of the vaccine. The scientists generated a ‘cocktail’ of four antibodies, resulting in a therapy which successfully cured six guinea pigs when it was administered on day three of infection.
Lead author, Professor Alain Townsend, of the MRC Human Immunology Unit at the University of Oxford, said: “A useful opportunity to uncover antibodies from healthy volunteers in vaccine trials is being missed. Presently, many experimental vaccines for life-threatening infections, such as H5N1 and H7N9 avian influenza to SARS and MERS, are entering clinical trials. We are strongly recommending that these trials include antibody isolation. It is a small, extra step that could lead to new antibody therapies from an increased pool of donors and with reduced risk.”
'Therapeutic monoclonal antibodies for Ebola virus infection derived from vaccinated humans’ was published in Cell Reports on 2 April 2019.
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