Department of Medical Physics, Royal Perth Hospital, Western Australia, 6001,
Valendar F Turner, John Papadimitriou, Barry Page, David Causer, Helman Alfonso, Sam Mhlongo, Todd Miller, Christian Fiala
Send response to journal:
MONTAGNIER'S REVERSE TRANSCRIPTASE ACTIVITY
AND ITS SPECIFICITY FOR RETROVIRUSES
In his rapid response: "Re: One AIDS patient will suffice", 6 July, Nicholas Bennett wrote: "As regards Montagnier's RT data, this opens up a whole new thread of discussion. I refer back to a Perth Group paper published in the magazine Continuum in Sept/Oct 1996 where they state:
(a) the presence of reverse transcriptase (RT) is proven indirectly, that is, by demonstrating transcription of the RNA template-primer A(n).dT15;
(b) the template-primer A(n).dT15 can be transcribed not only by RT but by other cellular DNA polymerases. All the cellular DNA polymerases, alpha, and gamma, can copy A(n).dT15. In fact, in 1975, an International Conference on Eukaryotic DNA polymerases, which included Baltimore and Gallo defined DNA polymerase gamma, "a component of normal cells", "found to be widespread in occurrence", whose activity can be increased by many factors including PHA stimulation, as the enzyme which "copies A(n).dT15 with high efficiency but does not copy DNA well"; it is impossible to say that the polymerase in the "growth medium" or in the material banding at 1.16gm/ml which catalyses reverse transcription of A(n).dT15 is RT or one of a number of other cellular DNA polymerases
This they use as evidence that Montagnier didn't adequately prove that RT had been detected. In fact, as happens frequently in Perth Group articles I find, the evidence to counter such conclusions is to be found in the very references they use to support their argument, refs. 2-5 in the original article [2-5 below also], which I looked up some 5 years ago.
In summary: Montagnier's RT prefers Mg2+ at 5mM and pH 7.8
DNA pol gamma prefers Mn2+ and a pH of 7.4
The key word is PREFERS. DNA pol gamma will work with Mg2+ at pH 7.4, but Montagnier was careful enough to check they were the optimal conditions, and for DNA pol gamma they are not.
Additionally, DNA pol alpha does not transcribe poly A-Oligo dT, but early reports stated it did because of contamination with DNA pol gamma.
Montagnier also used further confirmatory methods, such as inhibition with Actinomycin D, which does not affect RT but does inhibit cellular DNA polymerases and RNA polymerases by binding to double-stranded DNA, which the Perth Group do not try to explain".
In his rapid response: Re: Where is the virus", 10 July, Nicholas Bennett wrote: "I also notice the conspicuous absence of Perth Group rebuttall to my criticisms of their RT argument: are they therefore willing to admit that Montagnier was successful in showing that RT and not any other enzyme was detected as banding at 1.16g/ml? Will they say whether this was due to a simple mis-reading of the original paper by Montagnier, a genuine mistake, or a deliberate omission to support their case? The statement about it being "impossible" to distinguish RT from a DNA polymerase when not only does a chemical exist (actinomycin D) but Montagnier actually performed this control, just demonstrates the Perth Group's inability to read the literature as well as their ignorance of molecular biology. Heaven forbid it was a deliberate attempt to mislead…."
The detection of reverse transcriptase activity raises two questions: is the activity due to the enzyme reverse transcriptase and is the enzyme specific to retroviruses.
Montagnier's RT data was discussed in many of our publications as well as in our recent rapid response "Did Montagnier discover HIV in 1983?", 24 June. Here, suffice to mention that in the interview Montagnier gave to the French journalist, Djamel Tahi, at the beginning he stated that RT activity "is truly specific to retroviruses", then he said RT was only "characteristic of retroviruses". After further questioning Montagnier replied: "Taken in isolation, each of the properties [including RT activity] isn't truly specific".
In the paper entitled "Characterisation of the RNA dependent DNA polymerase of a new human lymphotropic retrovirus (lymphadenopathy associated virus)", Montagnier has reported that actinomycin inhibits the "HIV" RT activity "by approximately 50%".
In fig. 2 of the same paper evidence is presented that the cellular DNA polymerases b and a transcribe the template primer poly(A).dT15. The condition used included "pH 7.8" and "5mM Mgcl2". (1)
Let's assume that using the template-primer poly(a).dT15, "ph 7.8" and "5mM Mgcl2", Nicholas Bennett detects reverse transcriptase activity in: (i) cell cultures; (ii) a "purified" virus preparation which actually contains cellular vesicles (cellular fragments) but in which no retroviral particles can be seen even after Roman effort;
what scientific reasons would he have to conclude that the reverse transcriptase activity detected in the cultures or in the "purified" virus, is due to the enzyme reverse transcriptase of a retrovirus and not to the cellular DNA polymerases?
In his rapid response "Re: The HUT-78 cell line", 19 July, Nicholas Bennett wrote: "In their recent treatise on cell lines, the Perth Group state that "a cell infected with a retrovirus, in order to express retrovirus particles and antigens, must be activated/stimulated, that is the cell must be treated with oxidising agents". Aside from the entirely too wishy-washy use of the word "oxidising" (which brings to mind such things as neat bleach and free radical damage to DNA), from experience, stimulation of cells hardly requires such harsh methods".
Would Nicholas Bennett please read references 2-7 and tell us if: (i) to stimulate cells and to obtain permanent cell lines, is or is not oxidation necessary; (ii) Montagnier, in 1983 and Gallo in 1984, treated their cells (Bru's lymphocytes, the umbilical cord blood lymphocytes and the H9 (HUT-78) cell line) with oxidising agents; (iii) Montagnier and Gallo consider stimulation (oxidation) necessary for the "production of viral [HIV] particles, antigenic expression and the cytopathic effect".
(1) Rey, M.A., Spire, B., Dormont, D., Barre-Sinoussi, F., Montagnier, L., Chermann, J.C. (1984), Characterisation of the RNA dependent DNA polymerase of a new human T lymphotropic retrovirus (Lymphadenopathy Associated Virus). Biochemical & Biophysical Research Communications, 121,(1), 126-133.
(2) Sekkat, C., Dornand, J & Gerber, M. (1988), Oxidative phenomena are implicated in human T-cell stimulation. Immunology, 63, 431-437.
(3) Papadopulos-Eleopulos, E. (1982), A mitotic theory. J. theor. Biol., 96, 741-758.
(4) Barré-Sinoussi F, Chermann JC, Rey F, Nugeyre MT, Chamaret S, Gruest J, et al. Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS). Science 1983;220:868-71.
(5) Popovic M, Sarngadharan MG, Read E, Gallo RC. (1984). Detection, Isolation and Continuous Production of Cytopathic Retroviruses (HTLV-III) from Patients with AIDS and Pre-AIDS. Science 224: 497-500.
(6) Zagury, D., Bernard, J., Leonard, R. et al. (1986), Long term cultures of HTLV-III infected cells: a model of cytopathology of T-cell depletion in AIDS. Science, 231, 850-853.
(7) Klatzmann, D & Montagnier, L. (1986), Approaches to AIDS therapy. Immunology, 319, 10-11.
Competing interests: None declared