In a new study published in the journal Cell, a team of researchers from Rockefeller University presents a possible new weapon against Zika, which is particularly dangerous for pregnant women due to its connection to a series of severe birth defects.
While the only way to prevent Zika currently is to avoid mosquito bites, antibodies generated by infected individuals in Mexico and Brazil present a possible avenue for developing a vaccine or other medical measures.
One such antibody – which the researchers call Z004 – particularly stands out.
“These antibodies could be very useful in the near future,” said co-lead author David Robbiani. “One could envision, for example, administering Z004 to safely prevent Zika among pregnant women or others at risk of contracting the disease.”
A Zika infection begins when the virus latches onto a host cell and penetrates its defenses. Upon recognizing a viral threat, the human immune system creates antibodies that identify the virus and prevent it from invading cells.
The team looked for antibodies that attack a specific part of Zika’s envelope protein – a protein on the surface of the virus that helps it launch an attack.
Working with collaborators in Santa Maria Mixtequilla, Mexico, and Pau da Lima, Brazil, the researchers received and analyzed blood samples from more than 400 individuals collected shortly after Zika began spreading through Latin America and the Caribbean.
After performing a deeper analysis of six of the most promising samples, the team noticed a surprising trend: five of them had the same species of nearly identical antibodies. Z004 – which was found in a Mexican volunteer’s blood – stood out among the effective antibodies.
While some vaccine candidates use all or most of the Zika virus to activate the immune system, the team believes it could be safer to use a tiny fragment featuring a unique ridge that is pinched by an antibody upon binding to the virus.
The dengue 1 virus – a close relative of Zika and one of four types of dengue – has a ridge that is quite similar to Zika’s. Z004 was also effective at neutralizing dengue 1.
Some of the Brazilian samples revealed evidence of prior dengue 1 infections, which could explain why certain volunteers’ immune systems were more effective at neutralizing Zika.
“It appears that, much like a vaccine, dengue 1 can prime the immune system to respond to Zika,” co-author Margaret MacDonald said.