Richard.Dewald@p0.f70.n382.z1.fidonet.org (Richard Dewald) (01/28/91)
Luc Montagnier, the co-discoverer of the AIDS virus, has
published some data substantiating his controversial idea that
the virus does not work alone in causing AIDS. He believes
that myoplasmas could be a significant co-factor in the
disease.
Mycoplasmas are small, single-celled organisms that resemble
bacteria, but they lack a cell wall. They are considered to
be the smallest living organism. The name cames from the
Greek word meaning "to mold."
In a paper published in December in the proceedings of the
French Academy of Sciences (L. Montagnier, et al, Comptes
rendus de l'Academie des sciences, 311:425 (1990)),
Montagnier's group at the Pasteur Institute in Paris, working
with collaborators at the Centre National de la Recherche
Scientifique in Marseilles, reports that antibodies against
mycoplasmal peptides can block HIV replication in a test tube.
This suggests, though it does not prove, that the mycoplasma
may cooperate somehow in the replication of the virus.
However, many experts believe that it is unlikely that a
single co-factor (as this kind of thing is called) is at work
in all cases of AIDS. Also, the data is still rather sketchy,
too much so to be conclusive.
The experiement was conducted by immunizing rabbits with a
specific peptide (small proteins, the product of the genetic
"program") from a sequence common to at least two species of
mycoplasma. The antibodies the rabbits produced inhibited
replication of the AIDS virus in fresh lymphocytes from HIV-
donors as well as in cells that were bred to be rich in CD4,
which is the receptor that HIV binds to in entering its target
cells.
The peptide used for the immunization is thought to be
involved in the binding of the mycoplasma to the cells it
infects. These results, if confirmed, could provide support
for Montagnier's notion that mycoplasmas and HIV work together
to attack the T-cells of AIDS patients. If the mycoplasma is
prevented from binding to the cell, HIV replication is
inhibited in some fashion.
The possibility that the antibody recognizes some structure of
the T-cell or on the virus cannot yet be ruled out. Montagnier
says his group looked for viral proteins recognized by the
antibody and couldn't find any.
Montagnier also isolated and cultured mycoplasmas from the
blood of HIV+ subjects, both symptomatic and asymptomatic. he
also found evidence of mycoplasmal DNA in HIV- subjects, but
the organism is apparently not present in concentrations high
enough to be cultutred. He has developed a theorhetical model
in which an orginally benign mycoplasmal infection serves as a
"genetic activator" of the immune system during HIV infection
and particularly of those cells in which the virus grows.
Mycoplasma is a good candidate as a co-factor in AIDS because
it is present everywhere.
-Science, v251, p. 271.
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