Nav: Home

Discovery of a Zika antibody offers hope for a vaccine

May 04, 2017

A research team based at The Rockefeller University has identified a potent new weapon against the Zika virus in the blood of people who have been infected by it. This discovery could lead to new ways of fighting the disease, including a vaccine.

In blood samples taken from subjects in Mexico and Brazil, the scientists found antibodies--proteins produced by the immune system--that block the virus from initiating an infection. These antibodies appeared to have been initially generated in response to an earlier infection by a related virus that causes dengue. One such antibody, which they call Z004, was particularly effective at neutralizing Zika.

"These antibodies could be very useful in the near future. One could envision, for example, administering Z004 to safely prevent Zika among pregnant women or others at risk of contracting the disease," says Davide F. Robbiani, a research associate professor in Michel Nussenzweig's lab. He and Leonia Bozzacco, a research affiliate in Charles M. Rice's lab, led the study, which appears in Cell on May 4.

The team's detailed examination of the interaction between this antibody and the virus also revealed a new potential strategy for developing a vaccine.

A precise target

A mosquito-borne virus, Zika usually causes mild symptoms in those who contract it. However, dramatic effects can appear in the next generation. Babies born to women infected during pregnancy are at risk of devastating neurodevelopmental abnormalities. The only way to prevent Zika is to avoid mosquito bites; there are currently no vaccines or other medical measures to do so.

An infection begins when the virus, traveling in a spherical particle studded with the viral envelope protein, latches onto a host cell and forces its way in. Faced with a viral threat, the human immune system generates antibodies that recognize the virus and stop it from invading cells. The team set out to find antibodies tuned to a particular target: a part of Zika's envelope protein, which the virus needs to launch an attack.

Five out of six

Through collaborators working in Pau da Lima, Brazil, and Santa Maria Mixtequilla, Mexico, they obtained blood samples from more than 400 people, collected shortly after Zika was circulating.

Individual responses to the same pathogen can vary greatly. Yet a deeper analysis of samples from six of the volunteers with the most promising antibodies revealed a surprise: Five of them contained the same species of nearly identical antibodies. This similarity suggested these molecules were particularly good at fighting the virus.

When the team examined these closely related antibodies' performance against Zika, one stood out: Z004, an antibody from a Mexican volunteer's blood. When given to mice rendered vulnerable to Zika, the antibody protected them from developing serious infections.

A shared ridge

To get a closer look at the interaction between the antibody and a fragment of the virus' envelope protein, scientists in Pamela J. Bjorkman's lab at Caltech determined the molecular structure formed as the two units interacted. Their detailed maps revealed how the antibody pinches a ridge on the virus when it binds to it.

While some efforts to develop a vaccine use all or most of the virus to stimulate the immune system, the researchers believe it could be safer to employ only a tiny fragment containing this ridge.

Zika isn't the only virus to sport the ridge, as it is also present in envelopes of other viruses in the same family. The dengue 1 virus, a close relative of Zika and one of four types of dengue, has a ridge that is remarkably similar to Zika's. When pitted against dengue 1, Z004 neutralized it as well.

A look back at samples from the Brazilians, collected six months before Zika arrived by a team led by Albert Ko of Yale University, revealed evidence of prior dengue 1 infections in some--and a potential explanation as to why certain people's immune systems fared better against Zika.

"Even before Zika, their blood samples likely had antibodies that could interact with this same spot on the envelope protein," says Margaret R. MacDonald, a research associate professor in Rice's lab. "It appears that, much like a vaccine, dengue 1 can prime the immune system to respond to Zika."
-end-
Nussenzweig is the Zanvil A. Cohn and Ralph M. Steinman Professor and Rice is the Maurice R. and Corinne P. Greenberg Professor in Virology.

Rockefeller University

Related Immune System Articles:

The immune system may explain skepticism towards immigrants
There is a strong correlation between our fear of infection and our skepticism towards immigrants.
New insights on how pathogens escape the immune system
The bacterium Salmonella enterica causes gastroenteritis in humans and is one of the leading causes of food-borne infectious diseases.
Understanding how HIV evades the immune system
Monash University (Australia) and Cardiff University (UK) researchers have come a step further in understanding how the human immunodeficiency virus (HIV) evades the immune system.
Carbs during workouts help immune system recovery
Eating carbohydrates during intense exercise helps to minimise exercise-induced immune disturbances and can aid the body's recovery, QUT research has found.
A new model for activation of the immune system
By studying a large protein (the C1 protein) with X-rays and electron microscopy, researchers from Aarhus University in Denmark have established a new model for how an important part of the innate immune system is activated.
More Immune System News and Immune System Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Teaching For Better Humans
More than test scores or good grades — what do kids need to prepare them for the future? This hour, guest host Manoush Zomorodi and TED speakers explore how to help children grow into better humans, in and out of the classroom. Guests include educators Olympia Della Flora and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#535 Superior
Apologies for the delay getting this week's episode out! A technical glitch slowed us down, but all is once again well. This week, we look at the often troubling intertwining of science and race: its long history, its ability to persist even during periods of disrepute, and the current forms it takes as it resurfaces, leveraging the internet and nationalism to buoy itself. We speak with Angela Saini, independent journalist and author of the new book "Superior: The Return of Race Science", about where race science went and how it's coming back.