Infection of a Spodoptera frugiperda cell line with Bombyx mori nucleopolyhedrovirus.

The interactions of Bombyx mori nucleopolyhedrovirus (BmNPV) with Spodoptera frugiperda cells (Sf9) were investigated. S. frugiperda cells are usually considered nonpermissive for BmNPV. However, in the present study, BmNPV DNA replication was observed and an increasing infectious titre, reaching 10(4) TCID50/ml on B. mori permissive cells by 6 days post-transfection, developed in the supernatant of infected Sf9 cells. Infection of Sf9 cells by BmNPV did not induce a discernible shutoff of cellular protein synthesis and no overt cytopathic effects were observed. These data indicate that the low permissivity of Sf9 cells for BmNPV replication is associated with an inapparent infection.