Less than a decade ago, Zika virus was causing panic across Central, Latin and South America. While the virus was less widespread than the recent coronavirus and most of the affected recovered, it was transmitted to fetuses of pregnant women. The virus has since been linked with serious ailments that include severe brain damage and vision impairment in these children.
Researchers have found that an antibody found in pregnant women who contracted Zika but didn’t pass the virus to their children, can shield mice from the virus and go on to combat it to an extent that it becomes undetectable. The discovery was made public in a study published in Cell by scientists from New York Presbyterian, the National Institutes of Health, and Weill Cornell Medicine.
During the Zika outbreak in Brazil in 2015, research for the study initially began when a few members of the team were on patient treatment duty. To check how the immune systems were responding to the virus, they took blood samples from the patients with special attention on pregnant women who did not pass the virus to their children. They found a common strong antibody called DH1017.IgM- an immunoglobulin M antibody.
IgM antibodies are released upon detection of an infection. These are usually weaker than IgG, the antibody that comes after IgM. However, this case saw it perform better than IgG. Upon structural analysis, a possible explanation was discovered. IgM had multiple ‘arms’ that allowed it to attach to multiple virus particles at the same time, making them easier to neutralize.
To find out if it worked in animals, the scientists infected a group of mice with the mosquito-borne virus. Half of the group was injected with the antibody a day before and a day after the infection while the other half was not. By the tenth day, all of the control group mice had died. All of the treated mice survived until the end of the 14-day observation period and their blood tests revealed that the virus was undetectable in their bloodstreams.
Researchers are of the view that the antibody could be used for patients who are at risk of contracting the virus, as well as those who have contracted the virus already. Researchers will try to find out if the antibody prevents pregnant mice from passing the virus to their offspring.
The chair of pediatrics at Weill Cornell as well as the co-senior author, Sallie Permar said, “The most devastating effect of Zika infection is the congenital infections, and therefore interventions that are developed must be tested in pregnant people. While early safety studies should be pursued in non-pregnant people and early efficacy studies should be pursued in pregnant animal models, those interventions that remain promising should move quickly into pregnant women.”
More preclinical research is being done. At the start of the year, a team from Walter Reed Army Institute of Research and Texas Biomedical Research Institute announced that it had successfully developed a vaccine that had a success rate of 80% at preventing mouse fetuses from birth defects that are caused by the virus. The vaccine uses inactivated Zika virus.