A team of researchers have identified the first human antibodies capable of protecting against all three pathogenic strains of the Ebola virus. The antibodies were isolated from a blood sample taken from a survivor of the recent Ebola outbreak, and they could be instrumental in developing a broadly effective vaccine against the viruses.
Infection with the Ebola virus is often fatal as there are no FDA approved vaccines or therapies to help protect against the pathogen and treat patients. The 2013-16 Ebola outbreak in Western Africa was the largest to-date, resulting in over 29,000 affected individuals and 11,000 deaths.
Researchers have focused on identifying monoclonal antibodies capable of binding to and neutralizing strains of Ebola virus, however current iterations are not broadly effective. While a therapy combining three monoclonal antibodies – known as ZMapp – is currently under development, it is only effective against the Ebola Zaire virus, and not against the related Sudan virus and Bundibugyo virus.
“Since it’s impossible to predict which of these agents will cause the next epidemic, it would be ideal to develop a single therapy that could treat or prevent infection caused by any known ebolavirus,” said Dr. Zachary A. Bornholdt, director of antibody discovery at Mapp Biopharmaceutical, Inc. The researchers published their findings in the journal, Cell.
Bornholdt and his colleagues isolated 349 monoclonal antibodies from the blood of a survivor of the recent Ebola epidemic. Of these antibodies, two were found to neutralize Ebola virus in cell culture. The antibodies – dubbed ADI-15878 and ADI-15742 – also had protective effects in animal models exposed to Ebola virus, Bundibugyo virus and Sudan virus.
The patient-derived antibodies were found to block the Ebola virus’ ability to infect cells and proliferate. According to the researchers, the genes responsible for allowing immune cells to generate the antibodies have also likely been identified.
“Knowing precisely where the antibodies attach to the glycoprotein molecules and when and how they act to neutralize ebolaviruses, we can begin to craft broadly effective immunotherapies,” said Dr. John M, Dye, professor of microbiology & immunology at Albert Einstein College of Medicine. “That knowledge has already allowed us to create a cocktail of monoclonal antibodies that we are testing in larger animal models for possible use in treating infected patients,” said Bornholdt.