Expanding the role of the virome: commensalism in the gut

Abstract

Viruses affect host physiology beyond causing acute disease, thereby giving rise to the concept that the virome is a component of the microbiome. However, the role of the enteric virome is understudied relative to the fast-paced research examining commensal bacteria in the intestine. In this article, I discuss our recent work on murine norovirus indicating that an animal virus in the intestine can provide many of the signals to the host that have been attributed to commensal bacteria. Our findings suggest that the surge in microbiome research should incorporate examination of the enteric virome.

FIG 1

Abnormalities in germfree mice are reversed by murine norovirus infection. Due to the absence of detectable bacteria, germfree mice display several abnormalities in the intestine and associated immune compartments, a subset of which are listed in the left column. Monoassociating germfree mice with murine norovirus (MNV) is sufficient to partially or completely reverse many of these abnormalities, as indicated in the right column (9). IFN, interferon; ISG, interferon-stimulated gene; TF, transcription factor.