Note: This letter was submitted to The Lancet on July 26th 1996 but was refused publication.

SIR -- The paper by Francoise Barr-Sinoussi (July 6th) raises several questions. We appeal for answers to a few of them:

(a) Barr-Sinoussi and Montagnier in 1983, Gallo in 1984 and their colleagues as well as all HIV/AIDS researchers since, determine the presence of "HIV reverse transcriptase" indirectly, that is, by measuring the transcription of the synthetic primer-template An.dT15. However, all the cellular DNA polymerases, alpha, beta and gamma, can copy An.dT15.(1) 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"(2), "found to be widespread in occurrence"(1), whose activity can be increased by many factors including PHA stimulation(3), as the enzyme which "copies An.dT15 with high efficiency but does not copy DNA well"(4). How is it possible then to claim An.dT15 reverse transcription in PHA activated cultures containing material derived from AIDS patients as proof for HIV isolation(5) or even the existence of HIV RT?;

(b) at present it is known that "...there are many reverse transcriptase-bearing entities other than retroviruses, including mobile elements found in a wide variety of eukaryocytes, some plant and animal DNA viruses, and even some introns (intervening sequences) found in certain fungal mitochondria genes"(6). These include healthy human and animal semen(7), bacteria(8) and hepatitis B virus(9). The latter can infect peripheral blood lymphocytes and monocytes(10) and PHA stimulation of HBV infected lymphocytes causes production of the virus.(11,12) The presence of RT in non- retroviral entities is accepted by some of the best known retrovirologists including Varmus and Kurth. "The hepatitis B viruses...replicate their DNA genomes via reverse transcription of an RNA intermediate. All members of this family contain an open reading frame (ORF), "P" (for pol), which is homologous to retroviral pol genes"(13) [pol=polymerase]. The cellular elements which contain RT include retrotransposons in which "RT genes are linked to genes that code for polyproteins with the potential to self- aggregate and to form core particles"(14). In view of the above data how is it possible to consider that RT is unique to retroviruses and indeed, "is the hallmark of a retrovirus"?;

(c) "Retroviruses are enveloped viruses with a diameter of 100-120 nm budding at cellular membranes. Cell released virions contain condensed inner bodies (cores) and are studded with projections (spikes, knobs)"(15). The definition of a retrovirus particle also includes the physical property that in sucrose density gradients they band at a density of 1.16 gm/ml. To date, no electron micrographs (EM) have been published of material banding at 1.16 gm/ml from cell cultures with tissues derived from AIDS patients. Furthermore, although many EM have been published of virus-like particles in non- banded material nobody(16,17), not even the CDC(18), or Hans Gelderblom and his colleagues who have most thoroughly studied these particles, have proven the existence in the cultures, of particles satisfying all the above morphological characteristics. In one of his latest publications Gelderblom and his colleagues have estimated that immediately after being released, "HIV particles" possess an average of 0.5 knobs per particle but it is also pointed out that "it was possible that structures resembling knobs might be observed even when there was no gp120 present, i.e., false positives"(19). What is the scientific justification then that the "Schematic diagram of HIV virion" in Figure 1 is studded with knobs? In the absence of proof for the existence of such knobs on "HIV virions", and if gp120 is found only in knobs as illustrated in the diagram and for infectivity the particles have to bind to CD4 "via the outer envelope protein, gp120", how is it possible for such HIV particles to be infectious? *

Eleni Papadopulos-Eleopulos (1) Valendar F.Turner (2) John M. Papadimitriou (3) David Causer(1)

(1) Department of Medical Physics, (2) Department of Emergency Medicine, Royal Perth Hospital, Perth, Western Australia; (3) Department of Pathology, University of Western Australia.

References

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2. Robert-Guroff M, Schrecker AW, Brinkman BJ, et al. DNA polymerase y of human lymphoblasts. Biochem 1977; 16: 2866-2873.

3. Lewis BJ, Abrell JW, Smith RG, et al. Human DNA polymerase III (R-DNA): Distinction from DNA polymerase I and reverse transcriptase. Science 1974; 183: 867-869.

4. Weissbach A, Baltimore D, Bollum F, et al. Nomenclature of eukaryotic DNA polymerases. Science 1975; 190: 401-402.

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19. Layne SP, Merges MJ, Dembo M, et al. Factors underlying spontaneous inactivation and susceptibility to neutralization of human immunodeficiency virus. Virol 1992; 189: 695-714.