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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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