From: yoga4you <no_reply@yahoogroups.com>
Date: Fri, Aug 1, 2008 at 3:28 AM
Subject: [shivayoga] HIV/AIDS cure
To: Shivayoga@yahoogroups.com
UT pathologists believe they have pinpointed Achilles heel of HIV
Medicine & Health / HIV & AIDS
Human Immunodeficiency Virus (HIV) researchers at The University of
Texas Medical School at Houston believe they have uncovered the
Achilles heel in the armor of the virus that continues to kill
millions.
The weak spot is hidden in the HIV envelope protein gp120. This
protein is essential for HIV attachment to host cells, which initiate
infection and eventually lead to Acquired Immunodeficiency Syndrome
or AIDS. Normally the body's immune defenses can ward off viruses by
making proteins called antibodies that bind the virus. However, HIV
is a constantly changing and mutating virus, and the antibodies
produced after infection do not control disease progression to AIDS.
For the same reason, no HIV preventative vaccine that stimulates
production of protective antibodies is available.
The Achilles heel, a tiny stretch of amino acids numbered 421-433 on
gp120, is now under study as a target for therapeutic intervention.
Sudhir Paul, Ph.D., pathology professor in the UT Medical School,
said, "Unlike the changeable regions of its envelope, HIV needs at
least one region that must remain constant to attach to cells. If
this region changes, HIV cannot infect cells. Equally important, HIV
does not want this constant region to provoke the body's defense
system. So, HIV uses the same constant cellular attachment site to
silence B lymphocytes - the antibody producing cells. The result is
that the body is fooled into making abundant antibodies to the
changeable regions of HIV but not to its cellular attachment site.
Immunologists call such regions superantigens. HIV's cleverness is
unmatched. No other virus uses this trick to evade the body's
defenses."
Paul is the senior author on a paper about this theory in a June
issue of the journal Autoimmunity Reviews. Additional data supporting
the theory are to be presented at the XVII International AIDS
Conference Aug. 3-8 in Mexico City in two studies titled "Survivors
of HIV infection produce potent, broadly neutralizing IgAs directed
to the superantigenic region of the gp120 CD4 binding site"
and "Prospective clinical utility and evolutionary implication of
broadly neutralizing antibody fragments to HIV gp120 superantigenic
epitope."
First reported in the early 1980s, HIV has spread across the world,
particularly in developing countries. In 2007, 33 million people were
living with AIDS, according to a report by the World Health
Organization and the United Nations.
Paul's group has engineered antibodies with enzymatic activity, also
known as abzymes, which can attack the Achilles heel of the virus in
a precise way. "The abzymes recognize essentially all of the diverse
HIV forms found across the world. This solves the problem of HIV
changeability. The next step is to confirm our theory in human
clinical trials," Paul said.
Unlike regular antibodies, abzymes degrade the virus permanently. A
single abzyme molecule inactivates thousands of virus particles.
Regular antibodies inactivate only one virus particle, and their anti-
viral HIV effect is weaker.
"The work of Dr. Paul's group is highly innovative. They have
identified antibodies that, instead of passively binding to the
target molecule, are able to fragment it and destroy its function.
Their recent work indicates that naturally occurring catalytic
antibodies, particularly those of the IgA subtype, may be useful in
the treatment and prevention of HIV infection," said Steven J.
Norris, Ph.D., holder of the Robert Greer Professorship in the
Biomedical Sciences and vice chair for research in the Department of
Pathology and Laboratory Medicine at the UT Medical School at
Houston.
The abzymes are derived from HIV negative people with the autoimmune
disease lupus and a small number of HIV positive people who do not
require treatment and do not get AIDS. Stephanie Planque, lead author
and UT Medical School at Houston graduate student, said, "We
discovered that disturbed immunological events in lupus patients can
generate abzymes to the Achilles heel of HIV. The human genome has
accumulated over millions of years of evolution a lot of viral
fragments called endogenous retroviral sequences. These endogenous
retroviral sequences are overproduced in people with lupus, and an
immune response to such a sequence that resembles the Achilles heel
can explain the production of abzymes in lupus. A small minority of
HIV positive people also start producing the abzymes after decades of
the infection. The immune system in some people can cope with HIV
after all."
Carl Hanson, Ph.D., who heads the Retrovirus Diagnostic Section of
the Viral and Rickettsial Disease Laboratory of the California
Department of Public Health, has shown that the abzymes neutralize
infection of human blood cells by diverse strains of HIV from various
parts of the world. Human blood cells are the only cells that HIV
infects.
"This is an entirely new finding. It is a novel antibody that appears
to be very effective in killing the HIV virus. The main question now
is if this can be applied to developing vaccine and possibly used as
a microbicide to prevent sexual transmission," said David C.
Montefiori, Ph.D., director of the Laboratory for AIDS Vaccine
Research & Development at Duke University Medical Center. The abzymes
are now under development for HIV immunotherapy by infusion into
blood. They could also be used to guard against sexual HIV
transmission as topical vaginal or rectal formulations.
"HIV is an international priority because we have no defense against
it," Paul said. "Left unchecked, it will likely evolve into even more
virulent forms. We have learned a lot from this research about how to
induce the production of the protective abzymes on demand. This is
the Holy Grail of HIV research -- development of a preventative HIV
vaccine."
Source: University of Texas Health Science Center at Houston
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