Since the early years of the AIDS epidemic, scientists have
recognized that HIV attacks white blood cells known as T
lymphocytes that display a molecule known as CD4 on their surface.
Studies have shown, however, that CD4 alone is insufficient to allow
the virus to infect these cells; another molecule is also required. In
their study, Dr. Berger and his co-authors identified that second
molecule and showed that it enables certain strains of HIV to fuse with
and enter CD4 positive (CD4+) T cells. The molecule, which the
Berger team dubbed "fusin," is a receptor for immune system proteins
called chemokines. The researchers showed that certain non-human
cells that normally are resistant to HIV become susceptible to infection
with the virus after the DNA encoding CD4 and fusin are introduced.
They also found that antibodies to fusin block HIV entry into human
cells that ordinarily would become infected.
"The study by Dr. Berger and his colleagues is extremely
important and well-deserving of the AAAS-Newcomb Cleveland
Prize," says NIAID Director Anthony S. Fauci, M.D. "The recent
discoveries made by Dr. Berger and other scientists have created
unprecedented opportunities for deciphering the HIV disease process,
and provide the scientific basis for developing new treatment and
Soon after the Berger team's seminal finding was published, they
and other researchers reported the discovery of a different chemokine
receptor used by other strains of HIV to enter and infect CD4+ cells.
Scientists conducted genetic studies of a group of individuals who
have remained HIV-negative despite multiple high-risk exposures to
the virus, and they found a defect in the gene that encodes this
chemokine receptor. These findings suggest that HIV infection might
be prevented or treated with vaccines or drugs that block the
Dr. Berger adds that applying the chemokine receptor findings to
the development of small animal models of HIV infection would be a
valuable tool in the search for anti-HIV drugs and vaccines.
"Transgenic mice and rabbits expressing human CD4 molecules
have been developed, but they support HIV replication poorly," says
Dr. Berger. "Transgenic animals expressing both CD4 and chemokine
receptors may be more useful."
Dr. Berger has been at NIAID since 1987 and has been chief of
LVD's Molecular Structure Section since 1995. He and his NIAID
colleagues share the 1995-96 Newcomb Cleveland Prize with
physicists from the University of Colorado and the National Institute
of Standards and Technology. Their report of the first creation of a
Bose-Einstein condensate, a state of matter predicted by Albert
Einstein in 1924, may advance the implementation of atomic lasers
and may help scientists gain a better understanding of
superconductivity and quantum mechanics.
Established in 1923, the AAAS-Newcomb Cleveland Prize is the
AAAS's oldest award. Awardees receive $5,000 and a bronze medal.
The Prizes will be presented next month at the AAAS annual meeting
in Seattle, Wash.
NIAID is a component of the National Institutes of Health (NIH).
NIAID conducts and supports research to prevent, diagnose and treat
illnesses such as HIV disease and other sexually transmitted diseases,
tuberculosis, asthma and allergies. NIH is an agency of the U.S.
Department of Health and Human Services.
NIAID press releases, fact sheets and other materials are
available on the Internet via the NIAID home page at