X-ray crystallographic structure of a Norovirus capsid.
We have been championing the virome since the inception of the AMI. We believe that with time, viruses will prove equally as important as bacteria within the microbiome. To this end, a paper published last week in Nature shows evidence that a specific virus can promote a healthy gut in mice the same way that bacteria do. The virus, murine norovirus (MNV), was able to successfully restore function to mice with compromised guts.
The authors started with two groups of mice, a control group and a germ-free group. The control group had normal guts and immune function as measured by gut morphology, and the amount of T-cells. The germ free mice had thin, leaky guts, and low levels of T-cells. The scientists infected these germ free mice with MNV and allowed it to proliferate. Upon investigation of these mice, their gut integrity and immune function resembled the control group. A second experiment was performed on mice that had been given a course of antibiotics that wiped out the normal microbiome and resulted in an abnormal immune system and compromised gut. When these mice were infected with MNV they too saw an improvement in health. In a final experiment mice were given pathogenic bacteria that damaged the gut, but when infected with the virus the negative effects from the pathogens were diminished.
Viruses have a bad reputation, but that’s because we generally only care about the ones that make us sick. There are countless viruses that exist in our guts though, many that we do not interact with at all, and many symbiotic ones which have yet to be discovered. It is time that we appreciate the entirety of our microbiome, not just the bacteria but the eukaryotes, archaea, fungi, and viruses as well.