Researchers at Vanderbilt University Medical Center and the Baylor College of Medicine in Houston are working to develop targeted treatments and vaccines against noroviruses.
According to the Centers for Disease Control and Prevention, each year in the United States norovirus is responsible for more than 20 million cases of acute gastroenteritis.
Symptoms of norovirus include severe abdominal cramping, diarrhea and vomiting.
There are several vaccine candidates in clinical trials. However, it is currently unclear how effective they will be, because of the periodic emergence of novel norovirus variants. According to the study, developing broadly effective vaccines will require an understanding of the genetic diversity of the virus and the different mechanisms the immune system can use to neutralize it.
Published in the journal Nature Communications, the article explains how the researchers isolated a panel of human monoclonal antibodies from subjects with a history of acute gastroenteritis that were cross-reactive and which neutralize a broad range of norovirus variants in laboratory tests.
Leading the research were, James Crowe Jr., M.D., director of the Vanderbilt Vaccine Center and B.V. Venkataram Prasad, Ph.D., the Alvin Romansky Chair in Biochemistry, in collaboration with Mary Estes, Ph.D., the Cullen Chair and professor of virology at Baylor College of Medicine.
According to the study, there is a conserved, antigenic site on the norovirus that could be used to reformulate vaccine candidates so that they are broadly effective against circulating viral strains. The monoclonal antibodies also could be used to treat or prevent norovirus infection directly or as diagnostic reagents.
“We were surprised to find naturally occurring antibodies that recognized so many different noroviruses,” said Crowe.
“Previously, many experts thought that this would not be possible because of the extreme sequence diversity in the various groups and types of noroviruses in circulation,” he said. “The human immune system continues to surprise us in its capacity to recognize diverse virus variants.”
“One of the fascinating aspects of this study was the unexpected finding of where the human antibody attacks the virus for neutralization,” Prasad said.
“It is exciting to now have human monoclonal antibodies that neutralize many norovirus variants,” added Estes.
The full study can be found here.
Norovirus is a contagious virus that causes vomiting and diarrhea. Symptoms can be so severe that intravenous fluids may be needed to combat dehydration, Norovirus can be spread from having direct contact with an infected person, consuming contaminated food or water or touching contaminated surfaces and then putting your unwashed hands in your mouth or lips.
The best defense against norovirus is frequent handwashing. Other preventative actions to stop the spread of norovirus include rinsing fruits and vegetables, cooking shellfish thoroughly, staying home when sick and for two days after symptoms stop, and avoiding preparing food for others when sick and for two days after symptoms stop.
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