A Yale study published on June 26 offers new insight into future treatments for norovirus, a leading cause of viral gastroenteritis worldwide. Researchers found that focusing immune responses in the gut may be crucial for developing effective vaccines and therapies against the highly contagious virus.
The findings, detailed in Science Translational Medicine, challenge previous vaccine development efforts that targeted antibodies circulating in the blood. Instead, the study highlights mucosal Immunoglobulin A (IgA) antibodies—primarily located in mucosal surfaces such as the intestines and gut—as essential for immune defense against norovirus.
"By using mouse models, we discovered that IgA was both necessary and sufficient for protection against norovirus," said Arya Ökten, first author of the study who recently completed her Ph.D. at Yale School of Medicine. The research team measured immune responses during norovirus infection and observed that while immunoglobulin G (IgG) appeared quickly in the blood, gut IgA developed more slowly but played a critical role in protection.
Further experiments with genetically engineered mice revealed that B cells and IgA were required to fight off infection; mice lacking these components lost their resistance to reinfection. Collaborating with Ted Kreider from the University of Pennsylvania, researchers used mRNA lipid nanoparticles to produce anti-norovirus IgA directly in mice, which fully protected them from infection.
The discovery suggests new treatment strategies could use mRNA technology to deliver protective IgA antibodies directly into patients' guts. Researchers noted that healthy adults might take several weeks to generate strong natural IgA responses after infection; however, this approach could be especially beneficial for immunocompromised individuals who suffer prolonged infections.
"We're now trying to figure out ways that we can test norovirus vaccine candidates that will elicit an IgA response," said Wilen. "It's a new immunological approach to the virus."
