Author Topic: Coffin claimed that 22Rv1 is the standard positive control - It shouldn't be  (Read 662 times)

Tango

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In this interview, John Coffin made the following claim.

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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.

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22Rv1 contains ≥10 proviral copies/cell (13), and was proposed to have been derived from an XMRV-infected tumor.

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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.

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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.

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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.




"I suspect there have been a number of conspiracies that never were described or leaked out. But I suspect none of the magnitude and sweep of Watergate." Woodward

"I would favor any name that does not impose (or give the appearance of imposing) taxonomic preconceptions on the nomenclature." Coffin

cath

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Let me see.

The XMRV env gen is not present in BALB/c and NIH3T3 genomic DNA.

It was present in early xenografts.

Where did it come from?


http://en.wikipedia.org/wiki/BALB/c

http://en.wikipedia.org/wiki/3T3_cells
« Last Edit: June 12, 2011, 03:51:53 PM by cath »

Patricia

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If they are using testosterone to increase the level of retrovirus in the 22Rv1, how can it possibly be the standard positive control for a retrovirus which naturally occurs at much lower concentration levels?  It seems to me if they use this hyper-activated sample as a positive control, they will not be able to detect the lower levels of the retrovirus which are occuring naturally. 

Is this what they are trying to do?  Ensure that the HGRV's will not be detected?
"Hell is empty.  All the devils are here."    ~ William Shakespeare, THE TEMPEST

Me:  They are at the IOM/HHS/NIH/CDC/CAA/PANDORA/WPI

Tango

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Yes, why use this as a control when the level of virus is artificially increased. 
"I suspect there have been a number of conspiracies that never were described or leaked out. But I suspect none of the magnitude and sweep of Watergate." Woodward

"I would favor any name that does not impose (or give the appearance of imposing) taxonomic preconceptions on the nomenclature." Coffin