Research
Immune System Disease
Fighting Ability
HIV Vaccine In Worldwide Trial
10-8-2003
Vanderbilt University Medical Center is participating in
worldwide tests of a potential vaccine that can stimulate
important immune responses against the virus that causes
AIDS.
This
is the first candidate vaccine against the human immunodeficiency
virus (HIV) to be studied simultaneously in so many locations,
from Brazil to Thailand, according to Merck & Co. Inc.,
which developed the vaccine.
Vanderbilt
currently is testing six potential AIDS vaccines, but the
Merck product has gone farther than any other in generating
cellular immune responses in preliminary human tests, says
Dr. Paul Spearman, co-principal investigator of the Vanderbilt
HIV Vaccine Program, one of nine U.S. sites to participate
in the study.
Cellular
immune responses refer to the production of a type of white
blood cell, known as a cytotoxic or "killer" T-cell,
which can clear its virus-infected neighbors from the bloodstream.
Scientists believe that by speeding up production of these
cells, a vaccine may be able to prevent the virus from spreading
in the body.
"It
may not prevent infection, but it might stimulate a response
that would prevent the disease that results from the infection,"
Spearman says.
The
Vanderbilt program is part of the federally funded HIV Vaccine
Trials Network, an international coalition of scientists
and institutions dedicated to accelerating the search for
an HIV vaccine. This is the first collaboration between
Merck and the network. The phase I trial is designed to
test – at varying doses -- the vaccine's safety and
ability to stimulate immune responses in healthy, uninfected
volunteers between the ages of 18 and 50. Of the 435 volunteers
who will participate in the study worldwide, about a dozen
will be tested at Vanderbilt.
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Volunteers will be randomly selected to receive three
injections of the either the vaccine or an inactive "placebo."
The study involves 24 clinic visits and 22 blood tests over the course
of 18 months.
A goal of the study is to see whether a single vaccine
can generate significant immune responses in diverse populations throughout
the world. If the trial is successful, more extensive testing will
be conducted, ultimately leading to studies in people at risk of being
infected with HIV.
The research is moving "fairly quickly,"
Spearman says. "We're really hopeful."
The vaccine consists of a synthetically produced HIV
gene – which cannot cause HIV infection. The gene is carried
by an adenovirus, which normally can cause symptoms of the common
cold, but which has been genetically altered so that is harmless.
Side effects of the vaccine in preliminary human studies have been
mild. They include soreness at the injection site and, at higher doses
than will be used in this study, flu-like symptoms in some people.
For more information about volunteering for this or
other HIV vaccine trials at Vanderbilt, visit the program's Web site
at http://www.hivvaccineresearch.com.
This story has been adapted from a news release issued
by Vanderbilt University Medical Center, www.mc.vanderbilt.edu/reporter/.
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