New research may lead to norovirus vaccine

Often given the moniker of “stomach flu,” norovirus is a common and contagious virus that causes vomiting and diarrhea. Now, researchers believe they may be on the path to uncovering how the virus works within the body and stopping it in its tracks.

The study, published in Gastroenterology, reveals how researchers were able to improve methods for studying the virus as well as how this research could be used to create vaccines of immunotherapies.

Norovirus is blamed for roughly 200,000 deaths each year across the globe, but understanding of the virus has been limited. Now, new research on the antibody-mediated response to the prominent and virile GII.4 strain from isolating monoclonal antibodies from infected patients may help develop new tools for fighting the virus.

The research team used a panel of 25 immunoglobulin G or A human monoclonal antibodies that recognized the GII.4 virus, and was able to determine the potential to block virus binding to cell receptors, according to the study. 

After isolating and characterizing these antibodies that neutralize the GII.4 norovirus, researchers say they are now on a path to better understand the human response to the virus and develop better treatments.

Lead author James Crowe, MD, director of the Vanderbilt Vaccine Center and professor of pediatrics and pathology, microbiology and immunology at Vanderbilt University Medical Center, said new techniques using human intestinal tissues allowed scientists to grow norovirus in the laboratory setting, something that was not possible using conventional cell lines in the past.

“These tools allowed our research team to identify human monoclonal antibodies from the circulating white blood cells of immune subjects that could be used to prevent or treat infection,” Crowe said.

Norovirus has been challenging to investigate in the past, due to the difficulty researchers had in propagating the virus in the research setting.

“When you can’t grow a microorganism, it is very difficult to develop and test vaccines. The new intestinal ‘organic’ cultures we used here get around that limitation,” Crowe said.

Another major hurdle has been the vast diversity or circulating norovirus.

“It isn’t clear that one vaccine could work for all noroviruses, since there are many different noroviruses that circulate,” he said. “Our current focus is to extend the work we just reported on antibodies to the dominant norovirus in the world right now-called GII.4 norovirus-to see if we can find human antibodies that inhibit all noroviruses. If we can find such immunity in people, that will teach us what parts of the norovirus particles need to be targeted to achieve a universal norovirus vaccine, instead of one that just covers some strains but not others.”

His team’s research on human antibodies will help test and develop new vaccines, Crowe said, and may even assist in developing some of the antibodies as treatments.

“The study may impact the field in two ways,” Crowe said. “First, the antibodies discovered in this work could be used a biological drugs to treat or temporarily prevent norovirus infection. Second, the detailed studies of how these antibodies work to inhibit norovirus teach us what we need new experimental vaccines to do in the human body. The antibodies show us that it is possible to induce very specific and effective immunity to norovirus.”