Vaccine Research
Summaries from the CDC HIV/STD/TB Prevention News Update
and links to Kaiser HIV/AIDS Reports on the Kaisernetwork and
other sources
Spring 2009 News Headlines and Briefly
New Strategy Proposed for Designing Antibody-Based HIV
Vaccine
- See NIAID Press Release
Researchers Develop Vaccine Candidate That Is Successful in Blocking Simian
Version of HIV
http://www.kaisernetwork.org/daily_reports/rep_index.cfm?DR_ID=58482
SUMMARY AND COMMENT
Developing an HIV Vaccine: We Bait, the Virus
Switches
April 22, 2009 |
Rajesh T. Gandhi, MD |
Infectious Diseases
One study demonstrates a promising technique
for identifying neutralizing antibodies against HIV; a second highlights the
challenge of HIV evolution to avoid T-cell responses.
Journal Watch STDs Alert for May 18, 2009
"British-Devised Test Helps to Narrow Search for Best
AIDS Vaccine"
Times (London) , (04.27.2009) Sam Lister
British researchers have reported a promising new development in the quest for
an AIDS vaccine: a laboratory test that detects whether a candidate vaccine will
generate a response from the body’s immune system, and whether the response will
actively fight HIV.
Early data suggest the test, called a viral inhibition assay, can differentiate
between immune responses that control HIV and those that do not. Developed by
Imperial College-London and the International AIDS Vaccine Initiative (IAVI), it
is now being evaluated in a Phase I AIDS vaccine trial. Scientists hope the test
will help them pick the best candidates for full trials while eliminating from
consideration those with little likelihood of generating an effective response.
A full trial can take three to five years, involve thousands of volunteers and
cost more than £100 million (US $148 million).
“The proof of concept is there. We feel it’s pretty reliable,” said Dr. Jill
Gilmour, IAVI’s director for clinical research and leader of the Imperial team.
“This is measuring something different to the current assays and arguably much
more relevant. We believe it can be a key frontline strategy and that it is
grounded in sound scientific hypothesis.” She noted, however, that the test’s
predictive potential can only be confirmed if a vaccine candidate has shown some
efficacy in larger trials.
“If we are able to tease out what looks promising and what doesn’t, then we have
a holy grail,” said IAVI President Seth Berkley. “At the moment, you get to a
point where it’s a ‘crapshoot’ as to what you take forward and what you don’t.”
A £40 million (US $59 million) grant from the UK Department for International
Development is funding the project.
London's Times Examines Test Aimed at Detecting Potential HIV/AIDS Vaccines
http://www.kaisernetwork.org/daily_reports/rep_index.cfm?DR_ID=58233
HIV Vaccine Development Faces Several Scientific
Obstacles, Fauci Says in Opinion Piece
http://www.kaisernetwork.org/daily_reports/rep_index.cfm?DR_ID=57797
See Winter News Archives
New Strategy Proposed for Designing Antibody-Based HIV
Vaccine
NIAID Press Release (6.14.09)
Most vaccines that protect
against viruses generate infection-fighting proteins called antibodies that
either block infection or help eliminate the virus before it can cause disease.
Attempts to create a vaccine that induces antibodies that prevent HIV infection
or disease, however, have so far been unsuccessful. But several recent studies
suggest promising new research directions for the development of an
antibody-based HIV vaccine, according to John R. Mascola, M.D., deputy director
of the Vaccine Research Center at the National Institute of Allergy and
Infectious Diseases of the National Institutes of Health, and colleagues.
These studies demonstrate
that, contrary to widespread belief, it is not uncommon for people infected with
HIV to naturally make antibodies that can neutralize a variety of HIV strains.
These antibodies do not protect people from the virus because they arise years
after HIV infection is established. However, if a vaccine could prime the body
to make these broadly neutralizing antibodies before exposure to HIV, they could
potentially prevent infection or hold the virus at bay until an army of immune
cells assembles to limit viral replication.
Based on these findings,
Dr. Mascola and colleagues recommend a research strategy that uses naturally
occurring, broadly neutralizing anti-HIV antibodies for the ultimate design of
an antibody-based HIV vaccine.
Key aspects of this
strategy include:
- Obtaining new broadly
neutralizing antibodies to HIV to expand the pool available for scientists
to study14.09)
- Identifying regions on
the surface of HIV that are vulnerable to broadly neutralizing antibodies
and determining the atomic-level crystal structure of those regions
- Understanding how
broadly neutralizing antibodies to HIV evolve and persist
- Clarifying the
structural differences between anti-HIV antibodies that do and do not have
neutralizing properties
- Determining what
quantity of broadly neutralizing antibodies an HIV vaccine must elicit to be
effective
- Learning how anti-HIV
neutralizing antibodies and HIV surface proteins evolve in response to one
another in people who eventually produce a powerful neutralizing antibody
response to the virus
- Clarifying how HIV
surface proteins are presented to the immune cells that produce broadly
neutralizing antibodies to HIV
- Determining what
immune-system conditions promote the production of broadly neutralizing
anti-HIV antibodies
ARTICLE:
L Stamatatos et al.
Neutralizing antibodies generated during natural HIV-1 infection: good news for
an HIV-1 vaccine? Nature Medicine DOI 10.1038/nm.1949 (2009).
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