Investigators Discover Antibody Capable of Inhibiting Multiple Strains of Norovirus

A team of investigators has made a key discovery that could make a vaccine for the norovirus a reality.

A study published in the journal Immunity describes how a research team discovered an antibody that is capable of broadly inhibiting several strains of pandemic norovirus.

“In order to design an effective vaccine for norovirus, scientists needed to identify a neutralizing antibody that could work against many strains of the virus, as well as strains that will circulate in the future,” Ralph Baric, PhD, an author on the study, said in a press release. “This information can now be used to build better human vaccines.”

Human noroviruses are the leading cause of acute gastroenteritis and account for nearly 1 in 5 cases of diarrhea and vomiting. Estimates from the US Centers for Disease Control and Prevention indicate that noroviruses cause approximately 200,000 deaths per year, which mostly occur in infants, children, and the elderly.

Although there are more than 30 genotypes of human norovirus, approximately 60% of outbreaks are caused by GII.4 genotype strains, which have caused periodic human pandemics.

The study team comprised investigators from the University of North Carolina at Chapel Hill Gillings School of Global Public Health, University of Texas at Austin, and the National Institutes of Health Vaccine Research Center. The team says that the most important discovery of their research is that a human antibody can bind to a conserved region of the virus that is common in the various strains, potentially neutralizing all GII.4 strains of norovirus that exist in nature.

A single antibody, A1431, showed broad blockade toward tested GII.4 strains and was able to neutralize the pandemic GII.P16-GII.4 Sydney strain. Further, structural mapping revealed conserved epitopes, which were occluded on the virion or partially exposed, allowing for broad blockade with neutralizing activity.

The discovery of a human antibody that can target conserved areas will provide broad protection for a prolonged period and vaccine developers can use this knowledge to determine how, and how often, to reformulate the vaccine over time.

“This study addresses a fundamental problem in norovirus disease development that could have wide-ranging impact on global health,” study author Lisa Lindesmith said in the press release. “We’ve established an understanding of the virus and how it changes, how the body’s immune response targets it and how we can use that information to make a better vaccine.”

The investigators worked alongside Takeda Vaccines, a leading vaccine manufacturer, which is developing a human norovirus vaccine that is currently in in phase 2b of clinical trials.

“Overall, our results provide high-resolution molecular information on humoral immune responses after [human norovirus] vaccination and demonstrate that infection-derived and vaccine-elicited antibodies can exhibit broad blockade and neutralization against this prevalent human pathogen,” the authors conclude in the article.