Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rare antibodies show scientists how to neutralize the many types of Ebola

13.09.2018

Two new studies by scientists at Scripps Research are bringing Ebola virus's weaknesses into the spotlight, showing for the first time exactly how human and mouse antibodies can bind to the virus and stop infection--not only for Ebola virus, but for other closely related pathogens as well.

The research suggests antibodies like these could be key ingredients in versatile lifesaving therapeutics capable of neutralizing all members of the Ebolavirus genus.


This figure from the mBio study offers a clue to Ebola vaccine design. A band across the center (waist) of the glycoprotein displays a continuum of key antibody epitopes. Those in regions A-C are targets for broad protection.

Credit: Ollmann Saphire lab, Scripps Research

"This is like understanding how to kill five or six birds with one stone," says Erica Ollmann Saphire, PhD, professor at Scripps Research and senior author of the new papers, published recently in mBio and the Journal of Infectious Diseases. "The different viruses in the Ebolavirus genus vary in their structure, but all these different viruses have the same outbreak potential. We need a therapeutic approach that can target them all."

A major challenge in treating what we call Ebola virus is that it isn't just one pathogen but five. Members of the genus Ebolavirus include Ebola virus, Sudan virus, Bundibugyo virus, Taï Forest virus and Reston virus. Each of these viruses is up to 50 percent different in amino acid sequence, making it tough to develop broad treatment strategies. For example, the Sudan and Bundibugyo viruses were responsible for 40 percent of Ebola cases before 2013, yet current experimental Ebola therapies can't neutralize them.

Adding to the threat, all members of the Ebolavirus genus could mutate to escape immune system defenses and fight off drug therapies.

The new research shows that antibodies that bind to a site on the viral "fusion loop" can neutralize all known ebolaviruses. The fusion loop is part of the machinery that the virus uses to fuse with human cells and initiate infection. Targeting this peptide could present an opportunity to develop a universal therapy for infections caused by all five members of the Ebolavirus genus.

For the mBio study, the researchers focused on a human antibody called ADI-15878. This antibody was found in the blood of an Ebola virus survivor and is the only human antibody ever found to neutralize all five members of the Ebolavirus genus.

So how does ADI-15878 do it?

Using a high-resolution structural technique called X-ray crystallography, the scientists modeled the interaction between the antibody and the viral glycoprotein (the protein that enables the virus to infect a cell). Ebola's glycoprotein is covered with sugars that help to mask the virus from detection by the body's immune system. The team observed that ADI-15878 binds directly to one of these sugars alongside a paddle-like structure on the fusion loop. Part of the antibody then dips down and binds into a pocket that is normally hidden by another part of the viral glycoprotein.

"It's really cool to see that this antibody has found a way to bind into a cryptic, conserved pocket despite the proximity of sugars and other pieces of the virus that effectively hide this region from the immune system" says mBio study first author Brandyn West, PhD, a research associate at Scripps Research.

The researchers hypothesize that this action locks two important parts of Ebola's fusion machinery together, making it impossible for the virus to get into human cells. The fusion loop is a key piece of the Ebola virus entry machinery, so its structure is what scientists refer to as highly conserved--meaning the virus can't easily mutate the fusion loop to escape immune detection without compromising the ability of the virus to infect cells. If antibodies targeting this structure were included in therapies or elicited through vaccines, these antibodies should provide broad protection.

But was ADI-15878 just a one in a million antibody from a lucky human survivor?

The second paper the lab published this week in the Journal of Infectious Diseases shows that such antibodies are not out of reach. In this work, the scientists showed that a mouse which had been sequentially immunized with Ebola virus and then Sudan virus also had a broadly protective antibody response. The researchers demonstrate that an antibody, termed 6D6, from this mouse binds to the same region as ADI-15878. The immunization study provides more evidence that this part of the fusion loop is a promising target for vaccine design and therapies.

"Both the human and mouse antibodies were able to neutralize all known types of Ebola," explains Jacob Milligan, PhD, research associate at Scripps Research and first author of the Journal of Infectious Diseases study.

It could be possible, the researchers say, for therapeutics to include antibodies that work like ADI-15878. Researchers working on Ebola vaccines could also design molecules that look like this region of the fusion loop. These molecules, called immunogens, teach the human immune system which piece of the virus to target.

"We're hot on the trail of immunogen design strategies to produce more of these neutralizing antibodies," Ollmann Saphire says.

###

Additional authors of the mBio study, "Structural basis of pan-ebolavirus neutralization by a human antibody against a conserved, yet cryptic epitope," were Crystal L. Moyer, Liam B. King, Marnie L. Fusco, Jacob C. Milligan and Sean Hui of Scripps Research. The study was supported by the National Institute of Health National Institute of Allergy and Infectious Diseases (grants U19 AI109762 and R01 AI132204). The research used resources of the Stanford Synchrotron Radiation Laboratory and Advanced Photon Source.

Additional authors of the Journal of Infectious Diseases study, "Structural Characterization of Pan-ebolavirus Antibody 6D6 Targeting the Fusion Peptide of the Surface Glycoprotein," were Diptiben V. Parekh and Katherine M. Fuller of Scripps Research; and Manabu Igarashi and Ayato Takada of Hokkaido University. The study was supported by the National Institutes of Health (grants R01AI132204, U19AI109762 and 5T32AI007354-27), Japan Agency for Medical Research and Development (AMED; grant JP17fk0108101), the Japan Society for the Promotion of Science (KAKENHI 16H02627).

Both studies used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

About Scripps Research

Scripps Research is ranked the most influential scientific institution in the world for its impact on innovation. A nonprofit research organization, Scripps expands basic knowledge in the biosciences and uses these fundamental advancements to develop profound innovations that improve well-being. Scripps researchers lead breakthrough studies that address the world's most pressing health concerns, accelerating the creation and delivery of medical breakthroughs to better human health across the globe. Our educational and training programs mold talented and committed students and postdocs into the next generation of leading scientists.

For more information about Scripps Research visit http://www.scripps.edu. Follow @ScrippsResearch on Twitter, Facebook or LinkedIn.

Media contact: Madeline McCurry-Schmidt, madms@scripps.edu, 858-784-9254

Media Contact

Madeline McCurry-Schmidt
madms@scripps.edu
858-784-9254

 @scrippsresearch

http://www.scripps.edu 

Madeline McCurry-Schmidt | EurekAlert!
Further information:
https://www.scripps.edu/news-and-events/press-room/2018/20180912-ebola-antibody-therapy.html
http://dx.doi.org/10.1128/mBio.01674-18

Further reports about: Ebola Ebola virus Infectious Diseases immune system

More articles from Health and Medicine:

nachricht Purdue cancer identity technology makes it easier to find a tumor's 'address'
16.11.2018 | Purdue University

nachricht Microgel powder fights infection and helps wounds heal
14.11.2018 | Michigan Technological University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>