A New Continuous Cell Line of Spodoptera exigua and Its Susceptibility to Autographa californica Multicapsid Nucleopolyhedrovirus

A continuous cell line, designated KU-SENL-1 (SENL1), has been established from minced neonate larvae of Spodoptera exigua (Lepidoptera: Noctuidae) treated with collagenase. The primary culture was maintained in TC100 medium supplemented with 10% Fetal Bovine Serum (FBS), 3% Helicoverpa armigera hemolymph and incubated at 27°C. This continuous cell line was cultured in TC100 medium supplemented with 10% FBS and subcultured at 5day intervals. The cell line consisted of a mixture of two cell types, epithelial-like cells and spindle-shaped cells, both of which grown as attached monolayers. The population doubling time of this new cell line during the logarithmic phase of growth was 45h. RAPD and DAF analyses confirmed that the origination of the SENL1 cell line was S. exigua. The susceptibility of this cell line to the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) was high and by 3 days postinfection (pi) greater than 90% of the cells contained Occlusion Bodies (OBs) or were greatly hypertrophied, indicating they were infected. This cell line was highly effective for Budded Viruses (BV) titration of the AcMNPV. Therefore, the SENL1 cell line will be a valuable new tool for biological characterization of AcMNPV in cell culture and also for protein expression using the baculovirus-insect cell expression vector system.