· The term "XMRV specific" is misleading. The primer probe set (primer 3f-8r) was complimentary to sequences in the env region of XMRV/VP62 and ERV-1. The term XMRV encompasses a wider range of variability than is allowed for here.
This is a very important point that the naysayers on HGRVs have yet to adequately address. Until they do, I will consider their attitude on the science of HGRVs to be pure hubris. I don't care how many arrogant scientists ignorant about ME/CFS and overconfident in their ability to detect viruses for which there is no gold standard assay say HGRVs are a no-go. They are still arrogant and ignorant and shouting in chorus doesn't change that. Gerwyn is right to keep insisting on this point.
· The real-time PCR actually established a figure of 68 copies per 100 cells for ERV-1 and 3 copies of ERV-1 per 100 cells in the CWR22 cell line. There is no history of this primer being able to detect XMRV/VP62 env sequences at a concentration of less than 2000 copies per 100 cells. The serial dilution method used here has come in for a great deal of criticism, and the copy number estimates in mice and the early CWR22 xenografts are highly likely to be unreliable.
This bit is full of statements that have not been adequately referenced, at least not as posted here. I have no idea where the information comes from. The intention of the statements has also not been adequately explained. Gerwyn leaves us guessing what he is trying to say. Things like this require in-line referencing and direct statements indicating objective - editors jace and Tango please take note. Without inline referencing and discussion they are not at all convincing. They are just claims stated as fact without any backup.
· Primer 3f-8r using a single round PCR was unable to detect XMRV/VP62 in the later xenograft.
and yet.... ??
why is this important? If the point of the letter is to educate, then every opportunity possible should be taken to actually explain your point. You do not do that here. You assume this statement speaks for itself but it does not. It is only obvious to people who already think like you about these issues and therefore it is incapable of educating or convincing anyone of anything.
The following information is erroneous:
· This is incorrect from the initial paragraph. The provirus detected was ERV-1 and not XMRV. There is no information on copy number of XMRVenv below 2000 copies per 100 cells. The proviral copy number was at most 68 copies per 100 cells and not 100 copies per 100 cells above. The authors are assuming that the assay could have detected XMRVenv, if present, even though this primer could not detect XMRV in later xenografts when used with the single round PCR.
To begin with, there is a big style problem here that undermines the clarity. You seem to be saying with the double negative that the information is actually correct. If you are going to be using a colon, it should either be followed by a block quote or by a simple list of the things which are incorrect. The colon followed by discussion as if it did not exist is very confusing and makes the reader irritated and want to skip over that bit because it makes no sense.
If you want to use the colon this bit should read
The following claims made in Paprotka et. all are incorrect: (list of untrue claims)
- The provirus detected was XMRV (indicate precisely where the claim was made with an inline reference).
- whatever you are trying to say is untrue about copy numbers (not at all clear here. And where the hell does the 68 copies part come from?)
- The assays were certain to be able to detect XMRVenv with single round PCR, implying that no false negatives were possible (inline reference needed to show where precisely the erroneous assumption was made)
(corrections of untrue claims)
First of all, the provirus detected was in fact ERV-1, not XMRV.(inline reference or discussion explaining how you know this)(and this is significant because....). Second, there is no information whatsoever provided in the paper or elsewhere to support the assumptions made about the sensitivity of the assays.(or whatever else you were trying to say) Finally, given the previous points, the assumption that there were no false negatives using these methods has no basis and is therefore scientifically reckless
More later.
