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Developing an HIV vaccine
AIDS is caused by the HIV (human immunodeficiency virus), which disrupts the body's immune system and impairs its ability to fight off disease. While researchers continue to develop drugs and therapies to treat patients infected with HIV, a concerted effort is also under way to develop an effective vaccine.
The aim of vaccination is to stimulate the production of an immune response strong enough to fight a specific infection. A healthy immune system mounts a strong, and usually effective, response when it detects a new virus or bacterium. A typical vaccine contains a disabled form of the target virus or bacterium, or only one of its key components.
The development of a new vaccine has three stages:
- Researchers identify a way to produce a harmless
form of the virus or of one of its components.
- Candidate vaccines are administered to a small number
of people to determine how their immune system responds.
- Vaccines are administered to thousands of volunteers
and their efficacy in preventing the targeted infection
is carefully monitored over time.
Standardizing an efficient and accurate measure of the immune response to a vaccine enables researchers to determine which vaccines are most effective, particularly during phase-two trials, and allows them to concentrate human and financial resources on the most promising candidates in larger phase-three trials.
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The world is closer to an HIV vaccine, thanks to the efforts of
the Canadian Network for Vaccines and Immunotherapeutics (CANVAC).
A unique network of 74 Canadian scientists in the public, private
and academic sectors, CANVAC is leading an international effort
to develop a standardized measure of immune response, which is crucial
to the development of an effective vaccine.
Researchers around the world are testing several candidates for
an HIV vaccine in laboratories and clinical trials. While these
scientists are keen to share data, there is no standard measure
of the immune response stimulated by a vaccine, making it difficult
to compare results.
Recognizing the importance of a standardized method, CANVAC began to recruit international partners. In July 2002, during an international AIDS conference in Spain, it attracted the support of two of the largest investors in AIDS vaccine research: the U.S. National Institutes of Health and the International AIDS Vaccine Initiative. Also supporting the initiative is BD Biosciences, a private-sector firm with operations in Mississauga, Ontario. Seven HIV vaccine-immune monitoring laboratories located in Canada, the United States and in Europe were chosen to participate in the first round of standardization.
"These groups had never sat at the same table to address this issue," recalls Dr. Aline Rinfret, associate scientific director of CANVAC. "Together, we drafted a strategy and agreed to participate in its execution."
The strategy includes the development of a standardized intracellular cytokine staining assay. Cytokines are proteins produced by cells of the immune system and are one of the hallmarks of an effective response.
Results of the first round of standardization were presented at a conference in May 2003. "The good news is that support for a standardized test is growing," says Dr. Rinfret. "The bad news is that it may take many months to achieve meaningful comparisons between results from different laboratories."
CANVAC is ideally suited to lead the effort to standardize. Unlike agencies that fund only research, CANVAC participates in projects that are likely to develop marketable products or intellectual property that can be patented or licensed.
More than 15 viral vaccines have been licensed and marketed in North America, mostly against such diseases as hepatitis, influenza, polio, measles and smallpox.
www.canvacc.org
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