In this interview, John Coffin made the following claim.
JOHN COFFIN: 22Rv1 is XMRV positive. It's the standard positive control.http://www.cfscentral.com/2010/12/dr-coffin-responds.html
This is a peculiar statement, as 22Rv1 is a cell line that has been treated with testosterone pellets used in the xenografting process.
As we all know, testosterone will ensure rapid replication of XMRV and hence will be nothing like a natural infection, or the level of virus found in blood.
These extracts are from Paprotka et al.
22Rv1 contains ≥10 proviral copies/cell (13), and was proposed to have been derived from an XMRV-infected tumor.
To explore the origin of the virus in 22Rv1 cells, we analyzed various passages of the CWR22 xenograft as well as a subline of the CWR22 xenograft (2152) from which the 22Rv1 cell line was established (12), and another prostate cancer cell line, CWRR1, which was also derived from CWR22 (16).
So they go looking for XMRV and find that the level of the virus increases over time, as the virus is exposed to more testosterone.
To quantify the amount of XMRV DNA in the CWR22 xenografts, we developed a real-time PCR primer-probe set that specifically detected XMRV env and excluded murine endogenous proviruses present in BALB/c and NIH3T3 genomic DNA (Fig. 1C). We used quantitative PCR of 22Rv1 DNA to estimate 20 proviruses/cell and used the 22Rv1 DNA to generate a standard curve. The CWR22 xenografts had significantly fewer copies of XMRV env (<1–3 copies/100 cells) compared to the 22Rv1 cells (2000 copies/100 cells). The CWR-R1 cell line had 3000 copies/100 cells, and the NU/NU and Hsd nude mice, thought to have been used to passage the CWR22 xenograft, had 58 and 68 copies/100 cells, respectively.
Making the next statement damn stupid.
We used the same XMRV-specific primer sets to amplify and sequence DNA from early passage xenografts (736, 777, 8L, 8R, 16R, and 18R; Fig. 2B); the results showed that XMRV env, but not gag sequences were present (sequencing coverage summarized in fig. S3), indicating that the early xenografts did not contain XMRV.