New Cell Lines fromHeliothis virescens: Characterization and Susceptibility to Baculoviruses

New cell lines from embryos ofHeliothis virescenswere recently developed. Six primary cultures were initiated in June 1995. From these initial cultures, two produced sufficient cell growth to allow subcultivation and eventually led to the establishment of seven cell strains, three of which are maintained at low temperatures (17°C). The strains were compared with a previously established cell line fromH. virescensby isozyme analysis and shown to be from the same species. All the strains were inoculated with various baculoviruses, includingAutographa californicanucleopolyhedrovirus (NPV),Anagrapha falciferaNPV,Anticarsa gemmatalisNPV,Rachoplusia ouNPV,Lymantria disparNPV (LdMNPV),Orgyia pseudotsugataNPV (OpSNPV),O. leucostigmaNPV (OlMNPV), andHelicoverpa zeaNPV (HzSNPV). All seven strains were highly susceptible to the noctuid NPVs, and large numbers of occlusion bodies (OBs) were produced in most of the inoculated cells. The HzSNPV infection developed at a slower rate (requiring 1 week or more before a substantial number of cells contained OBs compared with 2–3 days for the other three noctuid NPVs). Three of theH. virescensstrains were also susceptible to OpSNPV although only 10–20% of the cells produced OBs with this virus. We did not observe cytopathology (CPE) in any cells inoculated with OlMNPV or LdMNPV. Our results suggest that these new strains can be useful for the study and possibly the production of baculoviruses for which no effective cell systems are available and for comparative studies on multiple virus species.