Murine Norovirus Pathogenesis and Immunity
Stephanie M. Karst
from: Caliciviruses: Molecular and Cellular Virology (Edited by: Grant S. Hansman, Xi Jason Jiang and Kim Y. Green). Caister Academic Press, U.K. (2010)
The first murine norovirus, murine norovirus 1 (MNV-1), was discovered in 2003. Since then, numerous murine norovirus strains have been identified and they were assigned a new genogroup in the genus Norovirus. Murine noroviruses share pathogenic properties with human noroviruses. Specifically, they are infectious orally, they spread between mice, and at least one strain, MNV-1, causes mild diarrhea in wild-type hosts. Furthermore, primary MNV-1 infection fails to elicit protection from a secondary challenge with homologous virus in at least some situations, which is similar to the lack of long-term protective immunity elicited by primary human norovirus infection. Investigators have now begun to extend basic knowledge of norovirus infection and immunity using this system. In particular, studies of murine norovirus infection have provided valuable information regarding the critical nature of innate immunity in controlling infection. Mice deficient in components of the interferon signaling pathway are highly susceptible to MNV-1-induced gastroenteritis, systemic infection, and ultimately death. The precise mechanisms by which interferon protects from serious murine norovirus infection are beginning to be elucidated and will provide potential antiviral targets for combating human norovirus infections. In addition, murine norovirus infection of mice provides a useful model with which to define conditions to elicit protective immunity, potentially providing important information for human norovirus vaccine design. For example, repeated exposure to high doses of MNV-1 may provide protection from mucosal re-infection read more ...