Israeli researchers develop vaccine that enables recovery of AIDS
patients' immune system
By David Brinn December 27, 2004
Five of the seven AIDS patients responded positively to the vaccine
developed by the Israeli research team.
A Hadassah University Medical Center research team has developed a
vaccine that significantly strengthens the body's immune system
against the autoimmune aftereffects of HIV infection, a breakthrough
that could dramatically make an impact in the treatment of AIDS
patients.
Close to a million cases of AIDS have been diagnosed in the US since
the beginning of the epidemic, with the HIV/AIDS virus claiming over
20 million lives. Another 39 million people are currently estimated to
be living with HIV/AIDS worldwide.
The researchers found that although treatment with the widespread AIDS
cocktail of medications kills the virus, the immune system continues
to kill healthy cells; this research focuses on developing a vaccine
that would arrest this autoimmune destructive process. The results of
this study were published in the latest issue of the prestigious
Journal of Clinical Virology.
"The HIV virus starts killing white blood cells in the body," lead
researcher Dr. Rivka Abulafia-Lapid told ISRAEL21c. "The AIDS cocktail
has been proven to be effective at fighting and treating the virus,
but we realized three or four years after patients received the
cocktail that their immune system does not always recover. We
investigated what was behind this, and found that there's an
autoimmune process that continues unabated despite the fact that the
patient is taking the cocktail."
New drugs called protease inhibitors, which first approved in 1995,
revolutionized the treatment of patients infected with the AIDS virus.
These drugs usually are taken with two other drugs called reverse
transcriptase inhibitors. The combined drug "cocktail" - also known as
highly active antiretroviral therapy (HAART)- has helped change AIDS
in the last few years from being an automatic death sentence to what
is now often a chronic, but manageable, disease. However, while the
virus disappears in many patients, their immune system remains
dangerously ineffective against foreign elements, and many of the
patients end up dying due to related complications.
"In about 50% of the cases, despite the disappearance of the virus, or
at least the virus being below detection level, the immune system does
not bounce back," said Abulafia-Lapid.
HIV, the human immunodeficiency virus, infects a type of white blood
cell called CD4, an integral component in the body's immune system. As
HIV attacks and destroys CD4 cells, the weakened immune system becomes
less able to fight infection and disease. HIV can also cause AIDS, the
last and most severe stage of HIV infection.
The Hadassah study was conducted between 1998 and 2002 with an
additional two-year monitoring period. Seven patients participated in
the study; five of the seven patients responded positively to the
vaccine developed by the research team.
Abulafia-Lapid was assisted by Yael Keren-Zur, at the Human Biology
Research Center directed by Prof. Henri Atlan, associated with the
Department of Biophysics and Nuclear Medicine, Ein Karem, Jerusalem.
The study was conducted in collaboration with Prof. Zvi Bentwich, and
Prof. Irun Cohen from the Weizmann Institute of Science.
The research was based on a suggestion made by Atlan some ten years
ago. This was based on the hypothesis that in addition to HIV causing
AIDS by invading and killing CD4 blood cells, HIV causes the body's
central immune system to start killing these cells independently of
the virus as a consequence of an autoimmune process.
For most AIDS patients, the central immune system does not recover
even if the HIV virus is almost eliminated through treatment with the
cocktail of medications. The Hadassah vaccine was designed to stop the
continuation of the autoimmune process.
Initially, the researchers identified CD8 cells which are involved in
the autoimmune process and are supposedly responsible for destroying
CD4 cells in the immune system. In the laboratory, the scientists
isolated the CD8 cells from a sample of the patient's white blood
cells and mixed them with CD4 cells, and showed that these CD8 cells
were involved in the killing process. At this stage, preparation of
the vaccine involved neutralization of these CD8 cells and preparation
of portions of ten million cells each to be used by injection under
the skin in order to trigger a vaccination against these harmful
cells.
"We were able to locate the white blood cells responsible - which were
programmed to kill the good cells in the body and we were able to
isolate them in clinical trials," said Abulafia-Lapid. "We cultured
them in a lab setting, and saw that they only grew destructive cells.
We killed them, injected the dead destructive cells within the form of
a vaccine. This teaches the body to see these cells as foreign and
they start fighting them and destroying them."
Seven patients were treated with the new therapeutic vaccine. Each
received between three and four injections in a six-month period.
Following treatment, the patients CD4 cell count was continually
monitored for another two years from their initial vaccination to
determine if the number of CD4 cells increased in the peripheral
blood, and subsequently, reinforced the strength of the immune system.
In five of the seven vaccinated patients, the CD4 cells increased by
more than 50 percent.
"After two years of treatment, we found that the cells had been
eliminated or were very low. After three injections of the vaccine,
five of the seven patients tested showed an increase in healthy white
blood cells, which brought them to a certain level considered good for
AIDS patients," said Abulafia-Lapid.
"Our aim was not to prevent infection by the virus but to strengthen
the immune system and use our vaccination treatment as a complement to
the antiviral medication (HAART)", said Abulafia-Lapid. "Since the
autoimmune process continues even after elimination of the virus, the
vaccine that we have developed is directed to stop this destructive
process. In other words, our vaccine complements the cocktail of
medications, to stop the body from continuing to destroy itself."
The researchers are continuing to develop the vaccine funded by a
grant from Hadasit, the Hadassah subsidiary that promotes and
commercializes the intellectual properties generated at Hadassah and
by the Center for the Study of Emerging Diseases.
"Now, we plan to conduct extended clinical trials. We've shown that
the vaccine is non-toxic and safe. It's not an easy treatment but
we've shown that patients benefit from it," said Abulafia-Lapid. "What
I envision is making the disease like a chronic infection - the
cocktail treats the virus and we help the immune system to recover and
allow the patient to continue his life and have his immune system
fight any new invaders."
http://www.israel21c.org/bin/en.jsp?enDispWho=Articles%5El870&enPage=BlankPage&enDisplay=view&enDispWhat=object&enVersion=0&enZone=Health&
----------------------------------------------------------------------
"Why would I listen to losers?" -- Arnold Schwarzenegger
"Long term commitment in relationships is only necessary because it takes
so damn long to raise children. Marriage may well be some kind of trick
to keep the males around beyond sexual satiation." -- Captain Compassion
"Progress is the increasing control of the environment by life.
--Will Durant
Joseph R. Darancette
res0mp8t@NOSPAMverizon.net
.
|
