Interferon lambda (IFN-λ) efficiently blocks norovirus transmission in a mouse model.

Human noroviruses are highly efficient in person to person transmission thus associated with explosive outbreaks of acute gastroenteritis. Outbreak control is limited to disinfection and isolation measures. Strategies to control the spread of noroviruses should be developed and models to study norovirus transmission will greatly facilitate this. Here, a mouse-to-mouse transmission model, in which mice develop acute murine norovirus (MNV)-induced diarrhea, was used to explore the role of interferon lambda (IFN-λ) in the control of a norovirus infection. Sentinel AG129 mice [deficient in IFN-α/β and IFN-γ receptors] that were co-housed with MNV-infected mice shedding high amounts of virus in their stool, developed a MNV-infection with associated diarrhea. Inoculation of such sentinel mice with an IFN-λ expression plasmid resulted in the production of circulating IFN-λ and upregulation of the expression of IFN-stimulated genes (ISGs) of the gut. Injection of the IFN-λ-expressing plasmid to sentinels prevents MNV-induced disease upon exposure to MNV-infected mice, as well as MNV replication in the small intestine, the associated signs of inflammation and the mounting of a specific IgG-based immune response. This demonstrates that IFN-λ can alone mediate protection against transmission of norovirus. The development of a simple delivery method for IFN-λ could be explored as a strategy to control norovirus outbreaks and protect vulnerable populations such as the elderly and immunocompromised.