Production of selected baculoviruses in newly established lepidopteran cell lines.

One key to the in vitro mass production of baculoviruses is the development of insect cell lines capable of producing high levels of extracellular virus (ECV) and/or occlusion bodies (OBs). For this study, 34 newly established cell lines from 10 lepidopteran species were screened for their ability to produce ECV and OBs from a variety of baculoviruses. The selected baculoviruses included: the alfalfa looper virus (AcMNPV); the celery looper virus (AfMNPV); the velvetbean caterpillar virus (AgMNPV), the bollworm virus (HzSNPV), the diamondback moth virus (PxMNPV), and the beet armyworm virus (SeMNPV). ECV titers were determined using TCID50 assays (50% tissue culture infectivity dose), with the presence or absence of OBs being noted. For AcMNPV, 28 new cell lines were tested, with eight producing AcMNPV ECV titers of 1.1-47.3 x 10(6) TCID50/ml and 11 producing OBs. For AgMNPV, six new cell lines were tested, with all producing AgMNPV ECV titers of 3.5-62.3 x 10(6) TCID50/ml and generating OBs. For HzSNPV, four new cell lines were tested with three lines producing HzSNPV ECV titers of 1.4-5.0 x 10(6) TCID50/ml, but none generating OBs. For PxMNPV, 10 new cell lines were tested with seven generating PxMNPV ECV titers of 4.7-232.6 x 10(6) TCID50/ml and eight producing OBs. Lastly, using qualitative or semiquantitative methods, homologous cell lines were tested for AfMNPV and SeMNPV production, all of which produced OBs. Overall, many of the cell lines tested were found to produce OBs and generate moderate to high levels of ECVs of one or more baculoviruses.