1992, 143, 145-148
Oxidative Stress, HIV and AIDS
E. Papadopulos-Eleopulos (1) V.F. Turner (2) and J.M. Papadimitriou
(1) Department of Medical Physics, (2) Emergency
Department and (3) Department of Pathology, (University of Western
Australia), Royal Perth Hospital, Wellington St., Perth 6001 (Western
As long ago as 1983, one of us (E.P.-E.) proposed that
oxidative mechanisms are of critical significance in the genesis of AIDS
(acquired immune deficiency syndrome). A prediction of this hypothesis
was that the mechanisms responsible for AIDS could be reversed by the
administration of reducing agents, especially those containing
sulphydryl groups (SH groups). The discovery of HIV resulted in a
broadening of this hypothesis in that it considered oxidative stress as
a principal mechanism in both the development of AIDS and expression of
HIV (Papadopulos-Eleopulos, 1988; Papadopulos-Eleopulos et al., 1989).
However, the general acceptance of the HIV hypothesis of AIDS completely
overshadowed this alternative hypothesis, and although many other
scientists have questioned the role of HIV in the causation of AIDS
(Duesberg, 1987; Root-Bernstein, 1990) Robert Gallo and most AIDS
researchers consider HIV to be the sole "sine qua non" cause of AIDS.
Notwithstanding, some flaws, especially recently, have appeared which
cast serious doubt on the prevailing HIV/AIDS hypothesis. Luc
Montagnier, the discoverer of HIV, is presently of the opinion that
cofactors are necessary for the appearance of AIDS (Lemaitre et al.,
1990). It has been accepted by researchers at the CDC that KS (Kaposi's
sarcoma), the first and most specific of the AIDS indicator diseases,
for which the explanation of the HIV hypothesis was put forward by Gallo
in 1982, is not caused directly or indirectly by HIV (Beral et al.,
1990). On the other hand, recent empirical observations from three
seemingly unrelated areas of AIDS research are in agreement with the
hypothesis that oxidative mechanisms play a critical role in HIV
expression and AIDS development.
(1) Pompidou et al. (1985a) and more recently researchers from many
other institutions (Lang et al., 1988; Brewton et al., 1989; Reisinger
et al., 1990; Hersh et al., 1991) have shown that a reducing agent,
diethyl dithiocarbonate, previously used as an immunomodulator, and
inhibitor of tumour promotion, may be useful in improving the immune
response in HIV infected individuals and in preventing and treating
AIDS. Other reducing agents have also been found to have similar effects
(Schulof et al., 1986; Wu et al., 1989).
(2) In 1989, Eck et al. measured the level of acid soluble-SH groups
in plasma and the intracellular concentration of reduced glutathione
(GSH) in peripheral blood mononuclear cells (PBMC) and monocytes in
HIV-infected patients: both were found to be significantly decreased.
Following the above report, Buhl et al. (1989) determined the
glutathione concentration (reduced, oxidised and total) in plasma and
lung epithelial lining fluid of symptom-free HIV seropositive
individuals: in both tissues, both the reduced and total GSH
concentration was found to be significantly decreased.
(3) In 1985, Pompidou et al. (1985b) and more recently many other
researchers including Anthony Fauci have shown that reducing agents
suppress the expression of HIV (Scheib et al., 1987; Bitterlich et al.,
1989; Kalebic et al., 1991).
Because of the possible therapeutic implications of reducing agents
in AIDS patients it is important to have a basic understanding as to
- reducing agents suppress the expression of HIV;
- asymptomatic HIV-infected individuals and AIDS patients have
decreased sulphydryl and total glutathione levels.
HIV expression and reducing agents
The answer to the first question is encompassed in basic retroviral
research conducted over half a century. It is well known that all cells
contain retroviral genomic sequences (Martin et al., 1981 ; Callahan et
al., 1989; Nakamura et al., 1991). Recently French researchers suggested
that human DNA also contains sequences which are homologous with the HIV
genome (Parravicini et al., 1988). Many eminent retrovirologists,
including Weiss, did not exclude the possibility that retroviruses with
gene sequences not originally present in cells may arise during the
lifetime of the animal by duplication and/or recombination of endogenous
proviruses or even by rearrangement of cellular DNA, caused by many
factors including the pathogenic process itself, and that retroviruses
may be the effect and not the cause of the disease (Weiss et al., 1971).
According to Temin (1974) who shared the Nobel prize with Baltimore
for the discovery of reverse transcriptase (RT) and who, from the time
of its discovery considered the enzyme to be constituent of all cells
not just retroviruses, the genome of a retrovirus (ribodeoxyvirus) may
arise by rearrangement of the normal cell genome by the following
mechanism. "A section of a cell genome becomes modified in successive
DNA(w) to RNA(-) to DNA transfers until it becomes a ribodeoxyvirus
genome. First, these sequences evolve as part of a cellular genome.
After they have escaped as a virus they evolve independently as a virus
genome. The time may be millions of years in germ-line cells and days in
somatic cells". In fact, Temin and Baltimore (1972) did not exclude the
possibility that, in at least some cases, particles which band at 1. 16
g/ml contain RT and have morphological characteristics similar to
retroviruses, may be nothing more than cellular fragments. Irrespective
of the mechanism it is a fact, firmly established from basic retroviral
research, that retroviruses can appear even in virus-free cultures with
a rate that can be accelerated a million-fold by radiation, infection
with other viruses and mitogens (Weiss et al., 1971 Aaronson et al.,
Of particular relevance to the present discussion is the fact that
all mitogenic agents including radiation exert their biological effect
by oxidation of cellular sulphydryl groups (Papadopulos-Eleopulos,
Montagnier and his associate David Klatzmann were the first to draw
attention to the fact that LAV infection of T4 cells in vitro does not
lead to HIV expression unless the cells are stimulated. "Infection of
resting T4 cells does not lead to viral replication or to expression of
viral antigens on the cell surface, while stimulation by lectins or
antigens of the same cells results in production of viral particles,
antigenic expression and the cytopathic effect" (Klatzmann and
Montagnier, 1986). Gallo also expressed the view that without
"activation" the T4 cells do not express virus (Zagury et al., 1986).
But, apparently, they did not realise that oxidative phenomena are
implicated in human T-cell stimulation (Sekkat et al., 1988).
As early as 1984 it was realised that in vivo HIV genomic sequences
are not always detected in tissues obtained from patients with ARC and
AIDS or, when found, the "signal" is low. According to Gallo and his
colleagues "this low signal intensity could also be explained by the
presence of a virus distantly homologous to HTLV-III in these cells"
(Shaw et al., 1984).
Anthony Fauci and his colleagues, on comparing the evidence obtained
from the study of macrophages in vivo and in vitro, concluded: "These
data indicate that the ability to isolate in vitro macrophage tropic
strains of HIV does not reflect in vivo infection of circulating
monocytes, but is related to phenomena of in vitro selection or
adaptation" (Massari et al., 1990).
Furthermore, (a) to date, with perhaps one exception, no two
identical HIV have been isolated, not even from the same person; in one
case where two sequential isolates were made 16 months apart, none of
the provirus in the first isolate was found in the second (Saag et al.,
1988); (b) the genetic data obtained in vitro does not correlate with
the data obtained in vivo - "To culture is to disturb" (Meyerhans et
al., 1989); (c) many, if not all, of the proviruses detected in vivo and
in vitro are defective.
This data led researchers at the Pasteur Institute and their
associates to conclude that (1) "the task of defining HIV infection in
molecular terms will be difficult", (2) "virus isolated from PBMC may be
produced by the complementation of defective genes or by recombination
between two of them" (Meyerhans et al., 1989; Wain-Hobson, 1989). Be
this as it may, of particular relevance to the present discussion is the
a) HIV has been isolated only from in vitro cultures;
b) no HIV can be isolated, unless the cultures, one way or the other,
are subjected to oxidative stress, even although the tissue from AIDS
patients is already oxidised; it may be then that oxidative stress is of
pivotal significance in the detection of all retroviruses including HIV.
If oxidation is a prerequisite for HIV expression, it follows that
reducing agents will have the opposite effect: HIV will not be expressed
in their presence.
Oxidative factors in AIDS patients
AIDS patients suffer from many opportunistic microorganisms. Like all
cells, these microorganisms require reducing equivalents, including SH,
for division and survival (Papadopulos-Eleopulos, 1982) which they
obtain to the detriment of body tissues. In AIDS patients, a decrease in
the level of SH may also result from malnutrition and diarrhoea.
However, opportunistic infections, diarrhoea and malnutrition cannot
account for the low level of GSH and acid-soluble SH found in
HIV-positive, symptom-free, well-nourished homosexuals and
Since viral production also requires thiols, which they obtain from
the host, it may be reasonable to assume that the decreased SH level in
HIV-positive individuals may be the result of HIV infection, as has
already been proposed for SIV-infected monkeys (Eck et al., 1991).
However, because for both HIV and SIV expression, oxidative stress is a
prerequisite, this cannot be the case, i.e. oxidation cannot be both the
cause and the effect of HIV expression (Papadopulos-Eleopulos et al.,
At first sight it appears that there is no common factor, apart from
HIV infection, linking the various AIDS risk groups. However,
homosexuals are exposed to relatively high levels of nitrites and anally
deposited sperm, drug abusers to opiates and nitrites, haemophiliacs to
factor VIII. All these are known potent oxidising agents which oxidise
many cellular reducing equivalents such as NADPH and all sulphydryl
groups, including those of cysteine (acid-soluble thiols)
In normal tissue almost all glutathione is found intracellularly in
the reduced form (GSH) where it is also synthesised from glutamic acid,
cysteine and glycine, in the presence of ATP and magnesium. Cysteine
which is the rate-limiting amino acid cannot be substituted by its
oxidised form, cystine. Oxidation of cysteine (acid-soluble SH) is also
known to decrease cellular ATP and magnesium concentration (Tateishi and
Higashi, 1978; Siliprandi et al., 1987). Malnutrition and diarrhoea may
also lead to cysteine, magnesium and ATP deficiency.
As a result of the decrease in cysteine, ATP and magnesium
concentration, the synthesis of glutathione will be inhibited. The
oxidising agents to which the AIDS risk groups are exposed would also
directly oxidise GSH to GSSG. GSSG is efficiently excreted from cells
(Sies and Akerbrum, 1984). Glutathione exported across the cell membrane
interacts with gamma-glutamyl transpeptidase, an enzyme which catalyses
the breakdown of glutathione by transferring the gamma-glutamyl group to
It should be noted that: cystine is one of the best acceptors for the
gamma-glutamyl group; with exception of the kidney and pancreas, the
highest activity of the enzyme is in the epididymis and seminal
vesicles; the highest concentration of its soluble form, apart from
urine and pancreatic juice, is in seminal fluid (Meister and Anderson,
1983). Thus, the systemic decrease of glutathione concentration in HIV
seropositive individuals may result from both, decrease in synthesis and
increased degradation. The oxidative stress to which the AIDS patients
are subjected would lead to cellular anomalies in many cells, including
lymphocytes, resulting in opportunistic infection, immunological
abnormalities and neoplasia.
All this argues in favour of oxidation as being a critical factor in
the pathogenesis of AIDS and HIV expression.
Aaronson, S.A., Todaro, G.J. & Scolnick, E.M.
(1971), Induction of murine C-type viruses from clonal lines of
virus-free BALB/3T3 cells. Science, 174, 157-159.
Beral, V., Peterman, T. A., Berkelman, R. L. et al.
(1990), Kaposi's sarcoma among persons with AIDS: a sexually transmitted
infection? Lancet, 1, 123-128.
Bitterlich, G., Larcher, C., Solder, B. et al. (1989),
Effect of D-penicillamine on the expression and propagation of the human
immunodeficiency virus by H9 T-lymphoblastoid cells. Drug Res., 39
(II).Nr 7, 824-828.
Brewton, G.W., Hersh, E.M., Rios, A. et al. (1989), A
pilot study of diethyldithiocarbamate in patients with acquired immune
deficiency syndrome (AIDS) and the AIDS-related complex. Life Sci., 45,
Buhl, R., Holroyd, K. J., Mastrangell, A. et al.
(1989), Systemic glutathione deficiency in symptom-free-HIV seropositive
individuals. Lancet, 11, 1294-1297.
Callahan, R., Chiu, I., Wong, J.F.H. et al. (1985), A
new class of endogenous human retroviral genomes. Science, 288,
Deusberg, P.H. (1987), Retroviruses as carcinogens and
pathogens: expectations and reality. Cancer Res., 47, 1199-1220.
Eck, H.P., Stahl-Hennig, C., Hunsmann, G. et al.
(1991), Metabolic disorder of early consequence of simian
imniunodeficiency virus infection in rhesus macaques. Lancet, 1,
Eck, H.P., Gmunder, H., Hartmann, M. et al. (1989), Low
concentrations of acid soluble thiol (cysteine) in the blood plasma of
HIV-1-infected patients. Biol. Chem. Hoppe-Selyer, 370, 101-108.
Hersh, E.M., Brewtom, G., Abrams, D. et al. (1991),
Ditiocarb sodium (diethyldithiocarbamate) therapy in patients with
symptomatic HIV infection and AIDS. J. Amer. med. Ass., 265, 1538-1544.
Katebic, T., Kinter, A., Poli, G. et al. (1991),
Suppression of human immunodeficiency virus expression in chronically
infected monocytic cells by glutathione, glutathione ester, and
N-acetylcysteine. Proc. nat. Acad. Sci. (Wash.), 88, 986-990.
Klatzmann, D. & Montagnier, L. (1986), Approaches
to AIDS therapy. Immunology, 319, 10-11.
Lang, J.M., Touraine, J.L. & Tr‚po, C. (1988),
Randomised, double-blind placebo-controlled trial of ditiocarb sodium
("Imuthiol") in human immunodeficiency virus infection. Lancet, II,
Lemaitre, M., Gu‚tard, D., H‚nin, Y. et al. (1990),
Protective activity of tetracyline analogs against the cytopathic effect
of the human immunodeficiency viruses in CEM cells. Res. Virol., 141,
Martin, M.A., Bryan, T., Rasheed, S. et al. (1981),
Identification and cloning of endogenous retroviral sequences present in
human DNA. Proc. nat. Acad. Sci. (Wash.), 78, 4892-4896.
Massari, F.E., Poli, G. & Schnittman, S.M. (1990),
In vivo T-lymphocyte origin of macrophage-trophic strains of HIV. J.
Immunol., 144, 4628-4632.
Mcister, A. & Anderson, M.E. (1983), Glutathione.
Ann. Rev. Biochem., 52, 711-760.
Meyerhans, A., Cheynier, R., Albert, J. et al. (1989),
Temporal fluctuations in HIV quasispecies in vivo are not reflected by
sequential HIV isolations. Cell, 58, 901-910.
Nakamura, N., Sugino, H., Takahara, K. et al. (1991),
Endogenous retroviral LTR DNA sequences as markers for individual human
chromosomes. Cytogenet. Cell. Genetics, 57, 18-22.
Papadopulos-Eleopulos, E., Hedland-Thomas, B., Causer,
D.A. et al. (1989), An alternative explanation for the
radiosensitization of AIDS patients. Int. J. Radiat. Oncol. Biol. Phys.,
Papadopulos-Eleopulos, E. (1982), A mitotic theory. J.
theor. Biol., 96, 741-758.
Papadopulos-Eleopulos, E. (1988), Reappraisal of AIDS.
Is the oxidation induced by the risk factors the primary cause? Med.
Hypotheses, 25, 151-162.
Papadopulos-Eleopulos, E., Hedland-Thomas, B., Causer,
D.et al. (1991), Changes in thiols and glutamate as consequences of
simian immunodeficiency virus infection. Lancet, 11, 1013.
Parravicini, C.I,., Klatzmann, D., Jaffray, P. et al.
(1988), Monoclonal antibodies to the human immunodeficiency virus p18
protein cross-react with normal human tissues. AIDS, 2, 171-177.
Pompidou, A., Delsaux, M.C., Telvi, L. et al. (1985a),
Isoprinosine and imuthiol, two potentially active compounds in patients
with AIDS-related complex symptoms. Cancer Res. (Suppl.), 45,
Pompidou, A., Zagury, D., Gallo, R.C. et al. (1985b),
In vitro inhibition of LAV/HTLV-III-infected lymphocytes by dithiocarb
and inodine pranobex. Lancet, II, 1423.
Reisinger, E.C., Kern, P., Ernest, M. et al. (1990),
Inhibition of HIV progression by dithiocarb. Lancet, 335, 679-682.
Root-Bernstein, R.S. (1990), Do we know the cause(s) of
AIDS? Perspect. Biol. Med., 33, 480-500.
Saag, M.S., Hahn, B.H., Gibbons, J. et al. (1988),
Extensive variation of human immunodeficiency virus type-1 in vivo.
Nature (Lond.), 334, 440-444.
Scheib, R.G., Parenti, D.M. & Simon, G.L. (1987),
Prolonged antiviral activity of D-penicillamine in human
immunodeficiency virus-infected homosexual. Men. Amer. J. Med., 83, 608.
Schulof, R.S., Scheib, R.G., Parenti, D.M. et al.
(1986), Treatment of HTLV-III/LAV-infected patients with
D-penicillamine. Drug Res. 36, (11),Nr 10, 1530-1535.
Sekkat, C., Dornand, J. & Gerber, M. (1988),
Oxidative phenomena are implicated in human T-cell stimulation.
Immunology, 63, 431-437.
Shaw, G.M., Hahn, B.H., Araya, S.K. et al. (1984),
Molecular characterization of human T-cell leukaemia (lymphotrophic)
virus type III in the acquired immune deficiency syndrome. Science, 226,
Sies, H. & Akerbrum, T.P.M. (1984), Glutathione
disulfide (GSSG) efflux from cells and tissues. Methods Enzymol., 105,
Siliprandi, N., Siliprandi, D., Bindoli, A. et al.
(1978), Effect of oxidation of glutathione and membrane thiol groups on
mitochondrial functions, in: Functions of glutathione in liver and
kidney (H. Sies & A. Wendel) (pp. 139-147). Springer-Verlag,
Tateishi, N. & Higashi, T. (1978), Turnover of
glutathione in rat liver, in "Functions of glutathione in liver and
kidney" (H. Sies & A. Wendel) (pp. 3-7). Springer Verlag,
Temin, H.M. & Baltimore, D. (1972), RNA-directed
DNA synthesis and RNA tumour viruses. Advanc. Virus Res., 17, 129-187.
Temin, H.W. (1974), On the origin of RNA tumour
viruses. Harvey Lect., 69, 173-197.
Wain-Hobson, S. (1989), HIV genome variability in vivo.
AIDS, 3, S13-SI8.
Weiss, R.A.Weiss, R. A., Friis, R. R., Katz, E. et al.
(1971), Induction of avian tumor viruses in normal cells by physical and
chemical carcinogens. Virology, 46, 920-938.
Wu, J., Levy, E.M. & Black, P. H. (1989),
2-Mercaptoethanol and n-acetylcysteine enhance T-cell colony formation
in AIDS and ARC. Clin. exp. Immunol., 77, 1-10.
Zagury, D.,Bernard, J., Leonard, R. et al. (1986), Long
term cultures of HTLV-III-infected cells: a model of cytopathology of
T-cell depiction in AIDS. Science, 231, 850-853.