Enteric virus Adenovirus F-40/41 (AdV F-40/41) causes gastroenteritis in humans but is difficult to study due to poor replication in cell lines and challenges with long-term cultivation [1]. Primary intestinal epithelial cells can cultivate AdV F-40/41, but this method is laborious and expensive [2]. Additionally, laboratory mice are not susceptible to AdV F-40/41 infection [1]. Thus, developing standardised tools for producing high-quality viral stocks, creating cell infection models reflecting the gastrointestinal tract, and finding ways to utilize mice for studying AdV F-40/41 is crucial.
This study aims to identify permissive enteric cell lines for efficient and stable propagation of AdV F-40/41 and to develop an in vivo mouse model for studying viral shedding. We selected HuTu 80 (duodenal), PLC/PRF/5 (liver), AGS (gastric), and QGP-1 (pancreatic enterochromaffin-like) cells based on their reported susceptibility to AdV infection [3-5].
Cells were infected with a clinical isolate of AdV F-40/41, and viral replication kinetics were assessed by PCR four days post-infection. Results showed all tested cell lines were permissive to AdV F-40/41. Serial passage maintained infectivity in AGS and PLC/PRF/5 cells after four passages, whereas HuTu 80 cells did not sustain viral replication beyond the first passage. The QGP-1 cell line is yet to be fully tested, including studies using spheroids generated from this cell line.
In a mouse model, 4-week-old mice were orally challenged with AdV F-40/41, and viral shedding in faecal pellets was analysed by PCR and in vitro infectivity. Results demonstrated rapid viral shedding in feces from 2-7 hours post-challenge, declining to low levels at 24 hours.
We have successfully developed models using multiple enteric-related cell lines to study AdV F-40/41 replication and a mouse model for viral shedding. These models are useful for testing novel compounds for virus attenuation and provide standardized, reproducible methods for cultivating AdV F-40/41.