Always ask the questions, “Who paid for the research and at what cost to the human body?” - SM
http://dailynews.yahoo.com/h/nm/20010723/hl/vaccine_1.html
Monday July 23 5:44 PM ET
By Amy Norton
NEW YORK (Reuters Health) - For the first time, scientists have used a
modified polio vaccine virus to at least partially block the vaginal
transmission of an HIV (news
- web
sites)-like virus in monkeys. They say the achievement opens up the
possibility of developing an HIV vaccine that stops the virus at its point of
entry during sex.
In experiments with monkeys that had been vaccinated against simian
immunodeficiency virus (SIV), a cousin to HIV, all remained healthy up to one
year after being exposed to SIV through vaginal transmission. Two of seven
monkeys given the vaccine were completely protected from infection, while two
others had lower levels of virus in their blood, suggesting at least partial
protection.
In a ``control'' group of monkeys that did not get the vaccine, all became
infected and half developed symptoms within a year.
Monkeys normally develop an AIDS (news
- web
sites)-like illness within 12 to 18 months of infection with the SIV strain
used in the study, Dr. Raul Andino of the University of California, San
Francisco, told Reuters Health.
He and his colleagues report their findings in the August 2nd issue of the
Journal of Virology.
A number of HIV vaccines are under development, including ones now in human
trials. The one used in this study is different, Andino explained, in that it
triggers an immune response in mucosal tissue--the type that lines the vagina
and rectum and could serve as a first line of defense against sexually
transmitted HIV.
``Mucosal surfaces may be the key to preventing infection,'' Andino said in
an interview.
To create their vaccine, Andino and his colleagues started with the Sabin
oral polio vaccine, which is known to elicit an immune system response in
mucosal tissue. They added fragments of genetic information from SIV to the
vaccine, which allows it to present SIV proteins to the monkey's immune system,
priming it to quickly attack SIV after infection.
If further animal research pans out, Andino said the next step would be to
test the effects of adding HIV genetic fragments to the Sabin vaccine. This
oral polio vaccine is no longer used in the US, due to rare instances in which
the vaccine has caused polio.
Still, Andino said that adding some HIV gene fragments to the vaccine would
be safe. And, he added, since the Sabin vaccine is known to confer long-lasting
immunity and is cheap and easy to administer, an HIV vaccine based on it could
be ideal for the developing nations being ravaged by AIDS.
But there remain many unknowns, including whether HIV and SIV sexual
transmission are similar enough for these monkey findings to translate to
humans.
``It's possible,'' Andino said, ``that HIV is more sneaky.''
SOURCE: Journal of Virology 2001;75:7435-7452.
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