DWV infection and replication at the early stage in vitro using honey bee pupal cells

Deformed wing virus (DWV) has been best characterized among honey bee viruses; however, very little is known about the mechanisms of viral infection and replication due to the lack of honey bee cell lines. To resolve this problem, we established in vitro system to reconstitute DWV binding and entry to the host cell followed by translation of the genome RNA and the polyprotein processing with honey bee pupal cells. Using this system, P-domain of VP1 was found to be essential for DWV infection/replication but not binding/entry to the cell. DWV efficiently infects/replicates in cells derived from early but not late pupa, suggesting that the undifferentiated cells are targeted for the viral infection/replication. Furthermore, we found that inhibitors for mammalian picornavirus 3C-Protease, Rupintrivir and Quercetin suppress DWV infection/replication, indicating that this in vitro system is also useful for screening a compound to modify the viral infection/replication. Our in vitro system should help to understand the mechanisms of DWV infection and replication at the early stage. ImportanceRecent decline of managed honey bee colonies has been driven by the pathogens and parasites. However, studying the mechanisms of pathogen infection and replication in honey bee at molecular and cellular levels has been challenging. DWV is the most prevalent virus in honey bee across the globe and we established in vitro system to reconstitute the viral infection and replication with the primary pupal cells. Using RNA-dependent RNA polymerase (RdRP) and the negative strand of DWV genome RNA as markers, we show that the pupal cells can support DWV infection and at least replication at the early stage. The results shown in this report indicate that our in vitro system helps to uncover the mechanisms of DWV infection and replication. Furthermore, it is also feasible to conduct a large scale screening for compounds to inhibit or stimulate DWV infection/replication.