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Published on: August 20, 2018
Propagation of Bombyx mori Nucleopolyhedrovirus in nonpermissive insect cell lines
Soo-Dong Woo1, Jong Yul Roh, Jae Young Choi
1Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763, Republic of Korea. sdwoo@cbnu.ac.kr
Abstract:
This study addresses the susceptibility of Spodoptera frugiperda (Sf9 and Sf21), Trichoplusia ni (Hi5), and S. exigua (Se301) cells to the Bombyx mori nucleopolyhedrovirus (BmNPV). Although these cells have classically been considered nonpermissive to BmNPV, the cytopathic effect, an increase in viral yield, and viral DNA synthesis by BmNPV were observed in Sf9, Sf21, and Hi5 cells, but not in Se301 cells. Very late gene expression by BmNPV in these cell lines was also detected via beta-galactosidase expression under the control of the polyhedrin promoter. Sf9 cells were most susceptible to BmNPV in all respects, followed by Sf21 and Hi5 cells in decreasing order, while the Se301 cells evidenced no distinct viral replication. This particular difference in viral susceptibility in each of the cell lines can be utilized for our understanding of the mechanisms underlying the host specificity of NPVs.
Insights
Bombyx mori nucleopolyhedrovirus (BmNPV) infects Spodoptera frugiperda (Sf9, Sf21) and Trichoplusia ni (Hi5) cells, but not S. exigua (Se301) cells. Sf9 cells showed the highest susceptibility, offering insights into NPV host specificity mechanisms.
Area of Science:
- Molecular Virology
- Insect Cell Culture
- Bacculovirus Research
Background:
- Insect cell lines are crucial models for studying baculovirus replication.
- Spodoptera frugiperda (Sf9, Sf21), Trichoplusia ni (Hi5), and S. exigua (Se301) cells are commonly used insect cell lines.
- Bombyx mori nucleopolyhedrovirus (BmNPV) is a significant baculovirus with a defined host range.
Purpose of the Study:
- To investigate the susceptibility of commonly used insect cell lines (Sf9, Sf21, Hi5, Se301) to Bombyx mori nucleopolyhedrovirus (BmNPV).
- To characterize the viral replication, gene expression, and cytopathic effects of BmNPV in these cell lines.
- To explore the potential of differential viral susceptibility for understanding NPV host specificity.
Main Methods:
- Infection of Sf9, Sf21, Hi5, and Se301 cell lines with BmNPV.
- Monitoring for cytopathic effects and viral yield.
- Quantification of viral DNA synthesis.
- Detection of very late gene expression using a beta-galactosidase reporter assay under the polyhedrin promoter.
Main Results:
- BmNPV infection induced cytopathic effects, increased viral yield, and viral DNA synthesis in Sf9, Sf21, and Hi5 cells.
- Se301 cells showed no significant viral replication or distinct viral activity.
- Very late gene expression was detected in the permissive cell lines.
- Sf9 cells exhibited the highest susceptibility, followed by Sf21 and Hi5, with Se301 being non-permissive.
Conclusions:
- Sf9, Sf21, and Hi5 cells are permissive to BmNPV, contrary to classical assumptions of non-permissiveness.
- Se301 cells are non-permissive to BmNPV, highlighting significant differences in host-virus interactions.
- The observed differential susceptibility provides a valuable system for elucidating the molecular mechanisms governing NPV host specificity.
