Reply to “Contamination of SVG p12 Cells with BK Polyomavirus Occurred after Deposit in the American Type Culture Collection”

Abstract

e W e thank Michael W. Ferenczy and Eugene O. Major for their informative historical background regarding the origins of various SVG cell lines and subclones. In their letter, the authors also provide independent confirmation of our results that SVG p12 cells (ATCC CRL-8621) are positive for BK polyomavirus (BKPyV) DNA (1). Their letter is particularly important since the laboratory of the authors is one of the pioneers in JC polyomavirus (JCPyV) research and is also the place where the SVG cells originated.We disagree that our recent paper (1) implies that all SVGderived cell lines are BKPyV contaminated. On the contrary, in our paper we concluded that SVG-A cells, derived by limiting dilution of the original SVG cell line, are BKPyV negative, which suggests that the source of the SVG-A cell line was BKPyV negative. This observation was confirmed by Ferenczy and Major.The impact of the BKPyV contamination on SVG research is presently difficult to estimate since many studies utilizing SVGderived cell lines lack a clear specification of the source of the cells (1, 2). This leads us to reemphasize the implications of our recent paper: researchers who have been using or are using SVG-derived cell lines should test their cells for the presence of BKPyV, and reviewers of such work should demand this testing in case this has not been performed.Finally, the evidence provided by Ferenczy and Major showing that the SVG cells in their possession do not contain BKPyV DNA certainly raises concerns about previous and present routines for cell handling at the ATCC.

Reply to Henriksen, S.; Rinaldo, C.H. Should SVGp12 Be Used for JC Polyomavirus Studies? Comment on “Prezioso et al. COS-7 and SVGp12 Cellular Models to Study JCPyV Replication and MicroRNA Expression after Infection with Archetypal and Rearranged-NCCR Viral Strains. Viruses 2022, 14, 2070”

“…This leads us to reemphasize the implications of our recent paper: researchers who have been using or are using SVG-derived cell lines should test their cells for the presence of BKPyV, and reviewers of such work should demand this testing in case this has not been performed”. This sentence, published by Rinaldo et al in 2014 in Journal of Virology [ 2 ], clearly urges researchers who have been using or are using SVG-derived cell lines to test their cells for the presence of BKPyV.…”

“…The laboratory of the authors where the study entitled “COS-7 and SVGp12 Cellular Models to Study JCPyV Replication and MicroRNA Expression after Infection with Archetypal and Rearranged-NCCR Viral Strains” was performed [ 3 ] has been carrying out polyomavirus research since 1990 and is one of the most important Italian laboratories for that very research, as documented by the authors’ publications on the matter. Since the expertise of this group is polyomaviruses, the researchers were perfectly aware of the paper by Henriksen et al, published in 2014 [ 4 ], of a letter to the editor by Ferenczy and Major published in the same year [ 5 ], and of the author reply by Rinaldo and colleagues [ 2 ].…”

“…On the basis of what has been published and suggested by Rinaldo et al in 2014 [ 2 ], the SVGp12 cell line, owned by the laboratory, was tested in order to exclude the possibility of the BKPyV contamination. Specifically, before every study involving SVGp12 cells and JCPyV and also as an initial characterization of the cells, each vial containing this type of cell was thawed and cultured in Eagle’s minimal essential medium (EMEM), supplemented with penicillin, streptomycin, and fetal bovine serum (FBS), incubated at 37 °C in the presence of 5% CO 2 , and propagated.…”