Antibodies may further search for Ebola vaccine
Blood from survivor of disease apparently contains means of disabling virus
In the blood of a survivor of the recent Ebola outbreak, a team of researchers has discovered a number of antibodies that seem to successfully combat the deadly virus in mice.
The findings, published in the journal Science, may help point scientists in the right direction for developing a vaccine to protect against Ebola.
“The results provide a framework for the design of new [Ebola] vaccine candidates and immunotherapies,” the study authors wrote.
The antibodies, isolated from the blood of a survivor of the 2014 Ebola outbreak, could also lead to a treatment for Ebola.
The researchers' finding “describes the first in-depth view into the human antibody response to Ebola virus,” said team leader Laura Walker, a senior scientist at Adimab LLC, a biopharmaceutical company based in Lebanon, N.H., which funded the study.
“What we were trying to do was understand the antibody response in survivors,” Walker, a co-author of the study, told LiveScience.com. “When you put [the antibodies] into mice, it prevents the virus from infecting cells. You can use those antibodies as a template. One can imagine designing a vaccine based on these antibodies.”
No vaccine has yet been designed using isolated antibodies in this way, according to LiveScience.com.
The 2014 Ebola outbreak in West Africa was the largest outbreak of the disease ever recorded, according to the Centers for Disease Control and Prevention. It infected more than 28,600 people and caused more than 11,300 deaths. Health officials struggled to curb the spread of the virus. The CDC coordinated with other U.S. government agencies, the World Health Organization, and other domestic and international health organizations, and deployed teams of public health experts to West Africa. The epidemic has ended, although the CDC says additional cases may continue to occur sporadically.
Many researchers had previously thought that the virus was especially deadly because it could incapacitate the body's immune response, in part by taking out some of the white blood cells that could manufacture antibodies to fight the invading pathogen.
Recent research, however, has shown that this may not be the case. Work published in the Proceedings of the National Academy of Sciences found that four Ebola patients treated at Emory University Hospital in Atlanta actually showed higher rates of activation in B and T cells – white blood cells involved in immune response.
For this work, the scientists used a platform launched by biotech company Adimab to profile the B-cell response to the Ebola virus using samples from one survivor of the recent outbreak, known simply as “Subject 45.”
The researchers found more than 300 antibodies that targeted the Ebola virus' surface glycoprotein, a structure that the virus uses to latch on to host cells. Recent mouse studies have revealed certain vulnerable sites on this glycoprotein, but only a few antibodies targeting these weak spots have been found in human survivors until now.
Scientists at the Scripps Research Institute and the U.S. Army Medical Research Institute of Infectious Diseases then analyzed the antibodies, finding that 77 of them appeared to be able to neutralize the Ebola virus.
The researchers also tried different antibodies in mice, injecting them with a single dose of antibodies two days after they were infected with a mouse-adapted form of the Ebola virus. Many of the antibodies offered significant protection at rates ranging from 60 percent to 100 percent, but the scientists found three particularly strong performers that each targeted a different weak spot on the virus' glycoprotein.