Drosophila Schneider 2 (S2) cells: a novel tool for studying HSV-induced membrane fusion

Drosophila S2 cells and mammalian CHO-K1 cells were used to investigate the requirements for HSV-1 cell fusion. Infection assays indicated S2 cells were not permissive for HSV-1. HVEM and nectin-1 mediated cell fusion between CHO-K1 cells and S2 cells when either CHO-K1 or S2 cells were used as target cells. Interestingly, PILRα did not mediate fusion between CHO-K1 or S2 cells due to a glycosylation defect of PILRα and gB in S2 cells. Fusion activity was not detected for any receptor tested when S2 cells were used both as target cells and effector cells indicating S2 cells may lack a key cellular factor present in mammalian cells that is required for cell fusion. Thus, insect cells may provide a novel tool to study the interaction of HSV-1 glycoproteins and cellular factors required for fusion, as well as a means to identify unknown cellular factors required for HSV replication.