Identifying antibodies for 75% of norovirus outbreaks, University researchers took a step forward in creating a vaccine for the virus after publishing a study on March 5.
The study, done in collaboration with researchers from the University of North Carolina at Chapel Hill and the National Institutes of Health, gave oral vaccine boosters to two subjects who had a history of norovirus infections to study the antibodies fighting the virus. The virus is the leading cause of vomiting and diarrhea in the U.S. and is sometimes referred to as the “stomach flu,” according to the CDC.
“Current norovirus cases just this winter surpassed the two peaks of two previous seasons, which means that norovirus cases are really near the epidemic range in the U.S.,” said Juyeon Park, first author of the study and postdoctoral researcher at the University. “That’s why we delved into (researching) norovirus — because it’s really prevalent.”
Like the flu, norovirus has many strands and variants, and mutates quickly, making it difficult to develop a vaccine for it. The research instead identified antibodies in the subjects who took the oral vaccine that could neutralize a broad span of norovirus variants.
This study found an antibody, called VX22, that neutralized a large range of strands of the virus, Park said. With this information, researchers analyzed how this antibody responded to the virus strands’ antigens, which is what triggers the immune system to create these antibodies.
“We now identified what is the target site these antibodies recognize in the antigen,” Park said. “We can now use this antigen information that is targeted by VX 22 … in the future design of vaccine antigens.”
In addition to helping vaccine research for norovirus, the antibodies can also aid in future research of therapeutic treatments for those already infected with the virus.
“This antibody has a really great therapeutic potential,” Park said. “It can really treat the norovirus illness and symptoms in our patients who get infected.”
From here, the research team is working to study different types of isotypes of the antibodies found, which determine where in the body they are typically found. The team originally studied isotype IgG of the antibody, found primarily in blood, and is now studying isotype IgA of the antibody, found in parts where norovirus primarily infects, such as the throat and respiratory tract.
Once the results are found, researchers hope to compare the efficacy in neutralizing the virus between these different versions of the antibodies to determine which of the isotypes works best against norovirus.
“With the IgA responses, one of the key outstanding questions (is) whether IgA neutralizes better or (provides) higher protective efficacy than the IgG isotype,” Park said. “Even though the sequences of the fat, which is the part of the body recognized (as) antigens, (are) the same.”
