Hopes for Zika vaccine in sight


Rebecca Pool

Friday, October 6, 2017 - 14:00
Image: Zika virus particles (red) shown in African green monkey kidney cells. [NIAID]
Using blood samples from an individual previously infected with Zika virus, US-based researchers have developed an antibody-based Zika virus therapeutic that protected monkeys from infection.
Because monoclonal antibodies are generally safe, they believe that this antibody cocktail might be appropriate for uninfected pregnant women.
Antibodies will likely cross the placenta, so the researchers hope that administration during pregnancy may protect both the pregnant woman and the fetus from the Zika virus.
"This is a promising intervention to prevent and treat ZIKV infection during pregnancy," highlights Professor David Watkins from Pathology at the University of Miami Miller School of Medicine. "We would like to develop this antibody combination and get it into clinical trials as soon as possible."
As part of the research, Watkins and colleagues isolated immune cells from the blood of an infected pregnant woman blood and used them to make 91 monoclonal antibodies; immune system fighters designed to bind to a specific part of an invading virus or bacterium to stop the infection.
They went on to identify three antibodies that bound to Zika virus surface proteins, and each neutralized the virus.
They then administered a combination of these antibodies to rhesus macaques and exposed the animals to Zika virus one day later.
During the 21-day study, all four monkeys who received the antibody cocktail showed no virus replication.
"We administered a cocktail of these three antibodies to nonhuman primates one day before challenging them with Zika virus that had been isolated from a pregnant woman during the 2016 epidemic in Rio de Janeiro," says Watkins. "To our surprise, this prophylactic treatment completely prevented the virus from taking hold in the animals."
"Since these antibodies have exceptional safety profiles in humans and cross the placenta, this combination could be rapidly developed to protect uninfected pregnant women and their fetuses," he adds.
Given that numerous antibodies have exceptional safety profiles in humans, the researchers reckon the cocktail could be rapidly developed to protect uninfected pregnant women and their fetuses.
Research is published in Science Translational Medicine.
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