Yield and activity of theHeliothis zea single nuclear polyhedrosis virus propagated in cloned and uncloned lines ofHeliothis cells

Summary Heliothis cell lines originated from different laboratories were characterized by isoenzyme analysis and then evaluated for their ability to produce the single nuclear polyhedrosis virus ofHeliothis zea (HzSNPV). A cloned cell line (designated Hzlb3), whose homogeneity was supported by both morphological and isoenzyme analysis, was derived from a parental line (Hzl). Significantly greater yields (about 10-fold) of tissue-culture-derived, non-occluded virus (TCNOV) were obtained when compared to the parental line. The Hzlb3 clone also gave significantly higher yields of TCNOV than the Hz3 and UND-K cell lines. Although lines Hzl, Hz3, and Hzlb3 produced significantly more polyhedral inclusion bodies (PIB) than line UND-K, the infectivity of PIB from UND-K equaled that of lines Hzl and Hzlb3.