An Insect Cell Line Persistently Infected with a Baculovirus-Like Particle

Abstract

A persistent infection by a baculovirus-like particle was found in the established lepidopteran (Heliothis zea) cell line, IMC-HZ-1. The virus caused CPE in less than 1% of the IMC-HZ-1 cells, as measured by phase-contrast and electron microscopy. Transmission tests showed that four lepidopteran cell lines were susceptible to the persistent virus (designated as IMC-HZ-1-NOV). In inoculated TN-368 cell cultures, 90–100% infection was achieved. The ultrastructure and development of IMC-HZ-1-NOV in cell cultures were similar to known baculoviruses, and it is probable that this persistent virus is a member of the family Baculoviridae. Two lepidopterous species (Estigmene acrea and H. zea) inoculated with IMC-HZ-1-NOV by intrahemocoelic injection and/’orper os feeding of larvae were not susceptible.

Nudivirus Genomics and Phylogeny

“…It has an enveloped rod-shaped virion and replicates in the nucleus of infected midgut and fat body cells (Huger 1966, Payne 1974, Payne et al 1977. Heliothis zea nudivirus 1 (HzNV-1), formerly known as Hz-1 virus or the non-occluded baculovirus Hz-1, was originally described as a persistent viral infection in the IMC-Hz-1 cell line isolated from the adult ovarian tissues of the corn earworm Heliothis zea (Granados et al 1978). It can also persistently infect several other lepidopterous cell lines, e.g.…”

Defective Particles from a Persistent Baculovirus Infection in Trichoplusia ni Tissue Culture Cells

“…The baculovirus HZ-1, persistent in IMC-HZ-1 cells, can productively infect TN-368 cells (Granados et aL, 1978) and can establish a persistent infection in TN-368 cells, as demonstrated by infectious centre assays and the detection of virus DNA sequences in TN-P cell nuclei. Persistent viral infections have been linked to temperature-sensitive mutations (Preble & Youngner, 1975) and to DI particles (Huang & Baltimore, 1970).…”

“…Granados et al (1978) observed virus particles in the nuclei of approximately 1 ~o of the cells and reported replication of HZ-1 virus in TN-368 cells. Kelly et al (1981) reported virus induction in IMC-HZ-1 cells following superinfection with other baculoviruses as well as u.v.-inactivated virus.…”

Intracellular Protein Synthesis During Standard and Defective Hz-1 Virus Replication

“…The Hz-1 virus was discovered in a persistently infected Heliothis zea cell culture, IMC-Hz-1 (Granados et al, 1978). Its host range in vitro includes Trichoplusia ni (TN-368), Spodoptera frugiperda (IPLB SF-212), Heliothis zea (IPLB-1075), Mamestra brassicae and Porthetria dispar (IPLB-65Z) (Granados et al, 1978;Ralston et al, 1981;Langridge, 1981;Kelly et al, 1981).…”

“…Its host range in vitro includes Trichoplusia ni (TN-368), Spodoptera frugiperda (IPLB SF-212), Heliothis zea (IPLB-1075), Mamestra brassicae and Porthetria dispar (IPLB-65Z) (Granados et al, 1978;Ralston et al, 1981;Langridge, 1981;Kelly et al, 1981). Persistent infections have been obtained in the T. ni and S. frugiperda cell lines (Burand et al, 1983b;Ralston et al, 1981).…”