ACMNPV IN PERMISSIVE, SEMIPERMISSIVE, AND NONPERMISSIVE CELL LINES FROM ARTHROPODA

Insect cell lines from Arthropoda represented by Lepidoptera, Coleoptera, Diptera, and Homoptera were evaluated for their ability to support replication of AcMNPV. In addition, some of the cell lines that were refractive to AcMNPV were tested with AcMNPV hsp70 Red, a recombinant carrying the red fluorescent protein (RFP) gene, for their ability to express this protein after inoculation. Of the 10 lepidopteran cell lines tested, only three cell lines from Helicoverpa zea (BCIRL-HZ-AM1), Lymantria dispar (IPLB-LD 65), and Cydia pomonella (CP-169) failed to support detectable viral replication as measured by tissue culture infectious dose 50 (TCID50) assay. Heliothis virescens (BCIRL-HV-AM1) produced the highest viral titer of 2.3 ± 0.1 × 107 TCID50/ml followed by Heliothis subflexa (BCIRL-HS-AM1) at 4.7 ± 0.1 × 106 TCID50/ml and Spodoptera frugiperda (IPLB-SF21) at 4.1 ± 0.1 × 106 TCID50/ml. None of the coleopteran, dipteran, or homopteran cell lines supported AcMNPV replication. However, when studies were performed using AcMNPV hsp70 Red, the dipteran cell lines Aedes aegypti (ATC-10) and Drosophila melanogaster (line 2), both expressed the RFP as well as the refractive lepidopteran cell lines from H. zea and L. dispar. No RFP expression was observed in any of the coleopteran or homopteran cell lines. Cell lines refractive to AcMNPV did not appear to be adversely affected by the virus, as judged by their ability to multiply, nor was there any indication of induced apoptosis, as assessed by deoxyribonucleic acid fragmentation profiles or cell blebbing, or both.