The human fetal glial cell line SVG p12 contains infectious BK polyomavirus.
The human fetal glial cell line SVG was generated in 1985 by transfecting primary fetal brain cells with a plasmid containing an origin-defective mutant of simian virus 40 (SV40). The cells, which express SV40 large T-antigen, support the replication of human JC polyomavirus (JCPyV) and have been used for JCPyV studies but also for other studies in which cells of neural origin were desirable. We intended to use the SVG p12 cells from ATCC for antiviral drug studies with JCPyV. However, during initial experiments, immunofluorescence microscopy controls unexpectedly revealed cells expressing the late viral proteins VP1, VP2/VP3, and agno. This was confirmed by Western blotting. Since our agnoprotein antiserum is specific for BKPyV agnoprotein, infection with BKPyV was suspected. Indeed, specific BKPyV PCR of SVG p12 supernatants revealed a viral load of >1 × 10(10) genomic equivalents/ml. Negative-staining electron microscopy showed characteristic polyomavirus virions, and infectious BKPyV was transmitted from SVG p12 supernatant to other cells. Long-range PCR covering the viral genome, followed by DNA sequencing, identified BKPyV strain UT as well as deletion derivatives. This was confirmed by next-generation sequencing. JCPyV (MAD-4) was found to infect apparently uninfected and BKPyV-infected SVG p12 cells. In total, 4 vials from 2 different ATCC lots of SVG p12 cells dating back to 2006 contained BKPyV, whereas the subclone SVG-A was negative. In conclusion, SVG p12 cells from ATCC contain infectious BKPyV. This may have affected results and interpretations of previous studies, and caution should be taken in future experiments.


OBJECTIVE
This work reveals that one of the most frequently used cell lines for JC polyomavirus (JCPyV) research, the SV40-immortalized human fetal glial cell line SVG p12 obtained directly from ATCC, contains infectious BK polyomavirus (BKPyV) of strain UT and a spectrum of defective mutants. Strain UT has been previously found in urine and in tumors of different patients but is also frequently used for research. It is therefore not clear if BKPyV was present in the brain tissue used to generate the cell line or if this is a contamination. Although productive JCPyV infection of SVG cells was not dependent on prior BKPyV infection, the unnoticed presence of BKPyV may have influenced the results of studies using these cells. The interpretation of past results should therefore be reconsidered and cells tested for BKPyV before new studies are initiated. The frequently used subclone SVG-A did not contain BKPyV and could be a useful substitute.
Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.
Stian
S
Henriksen
Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway.
Garth D
GD
Tylden
Transplantation & Clinical Virology, Department of Biomedicine (Haus Petersplatz), University of Basel, Basel, Switzerland.
Alexis
A
Dumoulin
Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway.
Biswa Nath
BN
Sharma
Transplantation & Clinical Virology, Department of Biomedicine (Haus Petersplatz), University of Basel, Basel, Switzerland Infectious Diseases & Hospital Epidemiology, University Hospital Basel, Basel, Switzerland.
Hans H
HH
Hirsch
Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway Metabolic and Renal Research Group, UiT The Arctic University of Norway, Tromsø, Norway christine.rinaldo@unn.no.
Christine Hanssen
CH
Rinaldo
D001739:BK Virus / Q000502:physiology*; D015153:Blotting, Western; D002478:Cells, Cultured; D004279:DNA, Viral / Q000235:genetics; D005333:Fetus / Q000166:cytology / Q000378:metabolism / Q000821:virology*; D005455:Fluorescent Antibody Technique; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007577:JC Virus / Q000502:physiology*; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism / Q000821:virology*; D027601:Polyomavirus Infections / Q000378:metabolism / Q000821:virology*; D060888:Real-Time Polymerase Chain Reaction; D014412:Tumor Virus Infections / Q000378:metabolism / Q000821:virology*; D054334:Viral Regulatory and Accessory Proteins / Q000378:metabolism; D014779:Virus Replication; D000086082:Viroporin Proteins
D004279:DNA, Viral; D054334:Viral Regulatory and Accessory Proteins; C042559:agnoprotein, polyomavirus; D000086082:Viroporin Proteins