Bile — the secret ingredient in understanding stomach bugs

Human noroviruses (HuNoVs) are the most common cause of acute gastroenteritis worldwide, sometimes proving fatal for young children, immunocompromised patients and the elderly.

The lack of a sufficient model to study HuNoVs in vitro has been a major barrier to achieving a full understanding of their replication, nature and evolution. However, a group of researchers has succeeded in engineering stem cells isolated from human intestines to develop into cultures of human intestinal enteroids (HIEs), the type of cell that HuNoVs infect.

The researchers endeavoured to see how effective these cultures are for hosting various HUNoV strains, but initially, no replication of these viruses in the HIEs was observed. When the team added bile to the culture, however, they found that the virus took hold. In fact, the more bile, the better.

Fluorescently marking a major HuNoV protein revealed that 35 to 45% of cells in the HIE culture were infected. And bile from animals could also be used to promote viral replication in the model.

The authors say the establishment of this new cultivation system could support the development of new diagnostics, vaccines and therapeutics, and advance research on HuNoV evolution, immunity and pathogenesis.

The research has been published in Science.