The use of commercial serum replacements in media for the in vitro replication of nuclear polyhedrosis virus

Two commercially available fetal bovine serum replacements, previously used in media for the culture of vertebrate and insect cells, were evaluated in comparison with fetal bovine serum (FBS) for suitability as medium supplements for the production of the Autographa californica nuclear polyhedrosis virus in fall armyworm cell cultures. The overall patterns of viral protein synthesis were similar in infected cells in each of the media supplements, but some differences were noted in quantities of individual proteins produced and in the temporal regulation of the synthesis. The release of extracellular budded virions (ECV) in all media began at about the same time and the rate of release was similar. However, the final concentration of ECV was consistently lower in medium containing either CPSR-1 or CPSR-3 than that in FBS supplemented medium. The number of occlusion bodies (OB) per cell was also less in the CPSR-1 medium. In the CPSR-3 medium the number OBs per cell produced was not significantly different from those in the FBS medium. The LC 50 value of the OBs bioassayed in neonate Spodoptera frugiperda produced in the CPRS-3 medium was significantly lower than that of OBs from FBS medium but the LC 70 and LC 90 values were not. Abnormal OBs, that is OBs that contained few or no occluded virions, were observed in cells in media with all three supplements.