[Establishment of human sapovirus culture method]

More than 40 years after the discovery of human sapovirus (HuSaV), we have established a HuSaV culture system in which HuTu80 cells derived from the human duodenum adenocarcinoma cell line are cultured together with the addition of bile acid as a supplement. In addition to being a common cell line, this system using HuTu80 cells is a versatile method because classical culture media are available, and it is easy to scale-up for culture. However, the number of culture days required to obtain sufficient viral titer, the confirmation of viral gene conservation for sample selection, and the method for passaging of HuTu80-cells were crucial. So far, 15 genotypes have been successfully propagated and stocked, and stable supply as research resources has been achieved. Due to the above efforts, we can now proceed with the production and analysis of antisera using purified antigens and the evaluation of inactivation conditions. This manuscript introduces the background for selection of the cell line and bile acids, and the topics that have been discussed since the publication, as well as future issues that were raised such as the expression of cytopathicity and elucidation of low UV-C sensitivity of fecal-derived HuSaV.