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Myra McClure and Retrovirus Contamination

Mithriel

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The WPI study sequenced virus that had been cultured. It was different from the prostate cancer one so unlikely to be caused by XMRV already in the tissue.

They had an evolutionary tree worked out by an expert which proved their work was solid.

Anyway, the tissue is grown from prostate cells, possibly from cancer cells, I don't know. The cells have to be treated to make them immortal. They are far removed from any human. If the original cells were infected every cell must be infected. This would give near 100% results in every study, including the prostate research and this has not happened.

It is the details that make contamination so unlikely. As a broad statement, prostate cell line, MuLV in prostate tissue, it sounds a possibility but the process makes it unlikely, or at least unlikely to occur without it being very obvious and very easy to check.

The whole contamination thing is a side issue, dealt with and proved wrong, we need to move on to doing proper, important science that will benefit us all.

Mithriel
 

ixchelkali

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Apparently Myra McClure's findings about that contamination have been disputed:

Evidence that ecotropic murine leukemia virus contamination in TZM-bl cells does not affect the outcome of neutralizing antibody assays with human immunodeficiency virus type 1.
Platt EJ, Bilska M, Kozak SL, Kabat D, Montefiori DC.

Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland, 97201, USA.

J Virol. 2009 Aug;83(16):8289-92. Epub 2009 May 27.

Abstract
The TZM-bl cell line that is commonly used to assess neutralizing antibodies against human immunodeficiency virus type 1 (HIV-1) was recently reported to be contaminated with an ecotropic murine leukemia virus (MLV) (Y. Takeuchi, M. O. McClure, and M. Pizzato, J. Virol. 82:12585-12588, 2008), raising questions about the validity of results obtained with this cell line. Here we confirm this observation and show that HIV-1 neutralization assays performed with a variety of serologic reagents in a similar cell line that does not harbor MLV yield results that are equivalent to those obtained in TZM-bl cells. We conclude that MLV contamination has no measurable effect on HIV-1 neutralization when TZM-bl cells are used as targets for infection.
The full text of the article is available here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2715758/?tool=pubmed

Maybe McClure is a bit quick to dismiss other researchers' findings as contamination?

The procedures described in the Alter/Lo paper laid the contamination question to rest for me. Besides, as Mark and others have pointed out, why would there be contamination of the ME/CFS patient samples and not the control samples? Contamination doesn't explain the disparate rates of X/PMLV infection between patients and controls. That would have to be either very sloppy science or malfeasance, which doesn't seem plausible to me.
 
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I'm not doubting what you are saying Mithriel. In fact I hope and believe thats true.

On the other hand I believe Myra McClure is a more than competent researcher and her 2008 study predated any involvement with Wessely and ME/CFS.

Which brings me back to my second proposition? That the human cell lines showed MLVcontamination because it was already there.
Hi Marco,

I wonder if you might find Laika Spoetnik's blog interesting? She's written a technical (but readable) commentary on the Lo/Alter paper and covered many of the issues relating to PCR methodology.

Sam

http://laikaspoetnik.wordpress.com/...h-the-mr-and-scratch-the-x-and-youve-got-mlv/