Mouse intestinal villi as a model system for studies of norovirus infection.

Noroviruses (NoV) are enteric caliciviruses that have been detected in multiple species of mammals, including humans. Establishing an efficient in vitro cell culture system for human norovirus (HuNoV) remains a challenge; however, its replication has been reported in 3D cultured Caco-2 cells and a clone of Caco-2 cells (C2BBe1), human enteroids and human B cells. Isolated mouse intestinal villi, with large diversity of intestinal epithelial cells, are a primary cellular model that has been shown to be permissive for the infection and replication of enteric viruses such as rotaviruses. We hypothesized that they could allow the infection and replication of the human noroviruses. In this report, we indicate that the isolated villi model of the mouse intestine is effective for the infection study and replication of the human noroviruses from faeces and environmental matrices (water, vegetables and air). For successful infection, the virus needs to be activated with trypsin. The virus has an average replicative cycle of 10 h, although viral particles with infectious capacity are found already at 2 hours post infection (2 h.p.i.). The model is efficient in obtaining abundant biological material and is ideal for studying the biological activity of the human noroviruses in the same cell model or for generating antibodies. Keywords: human norovirus; intestinal epithelial cells; intestinal villus isolation; norovirus isolated from water; norovirus isolated from plants; norovirus isolated from air.