Brian T Foley,
Los Alamos National Lab, Los Alamos NM 87545
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The Perth group stated:
"Barre-Sinoussi and Chermann, the principal and the 2nd author of the 1983 Montagnier et al paper who, in 1973, used it to purify the murine sarcoma virus and to obtain material which contained nothing else but particles with “No apparent differences in physical appearance” (1)"
In fact, this paper states on 240 in Results:
in the Discussion on page 243, they correctly note that what they have
purified or enriched is not a single virus, but a mixture of at least
two species of viruses:
This is because the Moloney Murine Sarcoma Virus has had its envelope gene replaced by the c-mos protooncogene which encodes a serine/threonine kinase. Without an env gene, the Mo-MSV is defective and cannot infect cells unless it is packaged into virions in which the env protein is provided by a helper virus which in this case is the murine leukemia virus.
Rodent genomes contain dozens of copies of endogenous retroviruses, some of which are nearly identical to the Moloney Murine Leukemia Virus. In addition, there are dozens of exogenous rodent retroviruses such as the Friend, Kirsten, SL3 and Abelson murine leukemia viruses. Whether or not these are all truly "different" viruses, or just different isolates of the same virus, is an open question. The point I want to make is that Sinoussi et al. did get viral particles that looked identical to each other by electron microscopy, but without molecular clones, sequences, or serological profiles they could only take the word of the people they obtained their 78A rat fibroblasts from, that these particles were derived from the Moloney strain of MSV and not the Kirsten strain or some endogenous mouse or rat retrovirus that had become activated. All of these retroviruses look alike.
In the 1980s, when cloning and sequencing and other techniques became available, many of these exogenous and endogenous, defective and competent viruses were cloned and sequenced. With this new genomic information, it became clear why the Sarcoma viruses cause various sarcomas and require a helper virus. For example, the Moloney Murine Sarcoma virus has no env gene, it has been replaced by the c-mos gene (which is called the v-mos gene when it is in the virus genome).
example of 100% pure virus that the Perth group cites is a paper by
Crawford and Crawford on Rous Sarcoma virus (now known to be one of
several strains of the Avian Leukosis Virus
The Rous Sarcoma Virus paper also states "DNA was barely detectable in the preparation; it would be equivalent to 2 x 10^5 molecular weight units per particle if it were actually present in the virus." again showing that this was not 100% "pure" virus and nothing else.
I fail to see why these two papers which describe centrifugation of retroviruses are accepted by the Perth group as meeting all of their criteria for isolation and purification of a virus, when similar papers describing the same procedures carried out with HIV-1 or HIV-2 are dismissed. It is especially irritating to me that they like the Moloney Murine Sarcoma Virus paper even when the authors state that the prepared virus is a mixture of at least two different viruses; the Moloney MSV and its MLV helper virus.
Competing interests: None declared