A research team at The Scripps Research Institute of La Jolla announced Thursday that they succeeded in modeling a critical part of a virus that sickens hundreds of thousands of people in West Africa.
The model could provide a target for a vaccine for the Lassa virus, estimated by U.S. health officials to cause 100,000 to 300,000 illnesses annually in places like Sierra Leone, Liberia, Guinea and Nigeria. The estimated death toll for Lassa fever includes as many as 5,000 people.
Compared with the far more deadly Ebola virus, Lassa has flown under the radar even though researchers said it has the potential for larger outbreaks.
According to the U.S. Centers for Disease Control and Prevention, about 10 to 16 percent of the people admitted annually to hospitals in some areas of Sierra Leone and Liberia have Lassa fever. Serious cases can lead to Ebola-like hemorrhaging, neurological disorders and loss of hearing.
The study by staff scientist Kathryn Hastie and professor Erica Ollmann Saphire models a piece of the viral structure, called the surface glycoprotein, of the overall virus family that includes Lassa, called arenavirus. Their report is scheduled to appear Friday in the journal Science.
Previous attempts to model the glycoprotein failed because traditional methods used on other viruses caused the one for Lassa to break apart, preventing a modeling attempt.
Because of the difficulties, it took Hastie a decade to develop a solution.
“Studying Lassa is critically important. Hundreds of thousands of people are infected with the virus every year, and it is the viral hemorrhagic fever that most frequently comes to the United States and Europe,” said Ollmann Saphire. “Kate’s study needed to be done.”
By creating mutant versions of important parts of the molecule, Hastie engineered a version of the Lassa virus surface glycoprotein that didn’t fall apart, according to TSRI. She then used this model glycoprotein as a sort of magnet to find antibodies in patient samples that could bind with the glycoprotein to neutralize the virus.
Her model of the structure of the Lassa virus glycoprotein, which turned out to be a unique design among viruses, is bound to a neutralizing antibody from a human survivor.
The next step is to test a vaccine that will prompt the immune system to target Lassa’s glycoprotein.
“There’s a tremendous global interest,” Ollmann Saphire said. “I think the world woke up when they saw the scale of the Ebola outbreak.”
She said that with Hastie’s techniques for solving arenavirus structures, researchers can now get a closer look at other hemorrhagic fever viruses, which cause death, neurological diseases and even birth defects around the world.
Researchers with Tulane University, Albert Einstein College of Medicine in New York and Zalgen Labs of Germantown, Maryland, contributed to the study. Funding came from the National Institutes of Health and the Burroughs Wellcome Fund of North Carolina.
—City News Service
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