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Archetype JC virus efficiently replicates in COS-7 cells, simian cells constitutively expressing simian virus 40 T
K Hara1, C Sugimoto, T Kitamura
1Department of Microbiology, School of Allied Health Sciences, Kitasato University, Sagamihara 228, Japan.
Insights
JC polyomavirus (JCV), a cause of progressive multifocal leukoencephalopathy (PML), can be cultured in COS-7 cells. This breakthrough allows for large-scale production and isolation of archetype JCV from urine samples.
Area of Science:
- Virology
- Molecular Biology
- Human Pathogens
Background:
- JC polyomavirus (JCV) causes progressive multifocal leukoencephalopathy (PML).
- JCV persists in the kidney and replicates to be excreted in urine.
- Archetype JCV regulatory regions in urine differ from rearranged regions in PML brain JCV.
Purpose of the Study:
- To investigate archetype JCV replication in COS-7 cells.
- To determine if COS-7 cells can be used for isolating archetype JCV from urine.
Main Methods:
- Transfection of archetype JCV DNAs into COS-7 cells (with and without SV40 T antigen).
- Detection of JCV replication using hemagglutination assay.
- Passaging of progeny JCV to fresh COS-7 cells.
- Infection of COS-7 cells with JCV-positive urine samples.
Main Results:
- Efficient replication of archetype JCV was observed in COS-7 cells expressing SV40 T antigen.
- SV40 T antigen is essential for JCV replication in COS-7 cells.
- Archetype regulatory regions remained conserved during replication, with minor rearrangements elsewhere.
- JCV was successfully recovered and produced from urine samples using COS-7 cell cultures.
Conclusions:
- COS-7 cells provide a viable system for culturing archetype JCV.
- This method facilitates large-scale production and isolation of archetype JCV from clinical samples like urine.
Abstract:
JC polyomavirus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), is ubiquitous in humans, infecting children asymptomatically and then persisting in the kidney. Renal JCV is not latent but replicates to excrete progeny in the urine. The renal-urinary JCV DNAs carry the archetype regulatory region that generates various rearranged regulatory regions occurring in JCVs derived from the brains of PML patients. Tissue cultures that support the efficient growth of archetype JCV have not been reported. We studied whether archetype JCV could replicate in COS-7 cells, simian cells transformed with an origin-defective mutant of simian virus 40 (SV40). Efficient JCV replication, as detected by a hemagglutination assay, was observed in cultures transfected with five of the six archetype DNAs. The progeny JCVs could be passaged to fresh COS-7 cells. However, when the parental cells of COS-7 not expressing T antigen were transfected with archetype JCV DNAs, no viral replication was detected, indicating that SV40 T antigen is essential for the growth of JCV in COS-7 cells. The archetype regulatory region was conserved during viral growth in COS-7 cells, although a small proportion of JCV DNAs underwent rearrangements outside the regulatory region. We then attempted to recover archetype JCV from urine by viral culture in COS-7 cells. Efficient JCV production was observed in COS-7 cells infected with five of the six JCV-positive urine samples examined. Thus, COS-7 cells should be of use not only for the production of archetype JCV on a large scale but also for the isolation of archetype JCV from urine.