Dublin Core
Title
Scientists Seek to Develop Successful AIDS Vaccine
Description
"WASHINGTON - Efforts to develop an AIDS vaccine received a shot in the arm Thursday from a monkey study that showed genetically engineered vaccines can trigger a crucial immune response against AIDS-like viruses..."
Creator
Rebecca Kolberg
Source
University of Tennessee Daily Beacon
Publisher
Knoxville, Tenn. : University of Tennessee
Date
1991-04-19
Language
English
Coverage
United States (Nation)
Text Item Type Metadata
Text
WASHINGTON - Efforts to develop an AIDS vaccine received a shot in the arm Thursday from a monkey study that showed genetically engineered vaccines can trigger a crucial immune response against AIDS-like viruses.
In recent years, scientific evidence has accumulated showing that two branches of the immune system must be activated to fully protect a person against the AIDS-causing human immunodeficiency virus, or HIV.
Genetically engineered HIV vaccines, considered by many the best strategy for preventing HIV infection in humans have been shown to kick into action the first branch - proteins called antibodies, which attack free-floating virus in the bloodstream.
However, there has been no solid evidence that such vaccines have the power to activate the second branch - white blood cells, called cytotoxic T-8 lymphocytes or "killer T cells," which destroy viruses hidden inside cells.
Now, researches from Harvard Medical School and Applied bioTechnology of Cambridge, Mass., report they have used genetically engineered vaccine to spur both antibody and killer T cell responses in monkeys infected with the monkey equivalent of HIV, the simian immunodeficiency virus or SIV.
"The ability to elicit a ... cytotoxic T lymphocyte response is very much sought after in relation to an AIDS vaccine. This is a very significant finding," said Dr. Dani Bolognesi, an AIDS vaccine expert at Duke University School of Medicine in Durham, N.C.
Although some scientists like Dr. Jonas Salk are pursuing vaccine approaches using killed whole HIV, many researchers think the best hope for immunizing the general public against HIV lies in genetically engineered vaccines. Such Vaccines hook up HIV genes essential to triggering immunity with viruses, like the smallpox virus, that further attract the immune system's attention. Genetically engineered vaccines are thought to pose less of a risk of accidentally infecting healthy people with active HIV than whole virus strategies. However, most have not produced as strong an immune response as may be necessary to fend off the deadly AIDS virus.
The latest findings "support the use of recombinant (genetically engineered) vaccines for the prevention of HIV infections in humans," Dr. Norman Letvin, an associate professor of medicine at Harvard, and his colleagues wrote in the journal <em>Science.</em>
Unlike most genetically engineered HIV vaccines now under development, Letvin's vaccine employed proteins from the core of a retrovirus, rather than pieces of its outer shell, or envelope.
Another study found no evidence of killer T cell response in chimpanzees given a genetically engineered HIV vaccine that, like Letvin's formula, used the smallpox virus, as an immune stimulant, but coded for production of only envelope proteins, Bolognesi said.
Last year, researchers from Johns Hopkins Medical Institutions in Baltimore reported that healthy people who received a recombinant HIV vaccine containing HIV envelope genes produced an unusual type of killer T cell response.
Those so-called cytotoxic T [?] lymphocytes only appear capable of killing HIV infected immune system cells, not all HIV infected cells throughout the body as cytotoxic T-8 lymphocytes should be able to.
In its study, Letvin's team gave two rhesus monkeys a genetically engineered vaccine containing genes coding for core proteins of SIV and gave two other monkeys a phony vaccine containing a horse herpes virus.
The two monkeys given active vaccine developed both antibody and killer T cell immune responses that lasted up to four months after inoculation, while no such response was seen in the monkeys given phony shots, Letvin said.
In recent years, scientific evidence has accumulated showing that two branches of the immune system must be activated to fully protect a person against the AIDS-causing human immunodeficiency virus, or HIV.
Genetically engineered HIV vaccines, considered by many the best strategy for preventing HIV infection in humans have been shown to kick into action the first branch - proteins called antibodies, which attack free-floating virus in the bloodstream.
However, there has been no solid evidence that such vaccines have the power to activate the second branch - white blood cells, called cytotoxic T-8 lymphocytes or "killer T cells," which destroy viruses hidden inside cells.
Now, researches from Harvard Medical School and Applied bioTechnology of Cambridge, Mass., report they have used genetically engineered vaccine to spur both antibody and killer T cell responses in monkeys infected with the monkey equivalent of HIV, the simian immunodeficiency virus or SIV.
"The ability to elicit a ... cytotoxic T lymphocyte response is very much sought after in relation to an AIDS vaccine. This is a very significant finding," said Dr. Dani Bolognesi, an AIDS vaccine expert at Duke University School of Medicine in Durham, N.C.
Although some scientists like Dr. Jonas Salk are pursuing vaccine approaches using killed whole HIV, many researchers think the best hope for immunizing the general public against HIV lies in genetically engineered vaccines. Such Vaccines hook up HIV genes essential to triggering immunity with viruses, like the smallpox virus, that further attract the immune system's attention. Genetically engineered vaccines are thought to pose less of a risk of accidentally infecting healthy people with active HIV than whole virus strategies. However, most have not produced as strong an immune response as may be necessary to fend off the deadly AIDS virus.
The latest findings "support the use of recombinant (genetically engineered) vaccines for the prevention of HIV infections in humans," Dr. Norman Letvin, an associate professor of medicine at Harvard, and his colleagues wrote in the journal <em>Science.</em>
Unlike most genetically engineered HIV vaccines now under development, Letvin's vaccine employed proteins from the core of a retrovirus, rather than pieces of its outer shell, or envelope.
Another study found no evidence of killer T cell response in chimpanzees given a genetically engineered HIV vaccine that, like Letvin's formula, used the smallpox virus, as an immune stimulant, but coded for production of only envelope proteins, Bolognesi said.
Last year, researchers from Johns Hopkins Medical Institutions in Baltimore reported that healthy people who received a recombinant HIV vaccine containing HIV envelope genes produced an unusual type of killer T cell response.
Those so-called cytotoxic T [?] lymphocytes only appear capable of killing HIV infected immune system cells, not all HIV infected cells throughout the body as cytotoxic T-8 lymphocytes should be able to.
In its study, Letvin's team gave two rhesus monkeys a genetically engineered vaccine containing genes coding for core proteins of SIV and gave two other monkeys a phony vaccine containing a horse herpes virus.
The two monkeys given active vaccine developed both antibody and killer T cell immune responses that lasted up to four months after inoculation, while no such response was seen in the monkeys given phony shots, Letvin said.
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