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Meds, Mind, Body & Benefits => Research News & Studies => Topic started by: Tadeys on September 11, 2013, 03:43:01 pm
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A vaccine for the monkey equivalent of HIV appears to eradicate the virus, a study suggests.
Research published in the journal Nature has shown that vaccinated monkeys can clear Simian Immunodeficiency Virus (SIV) infection from their bodies.
It was effective in nine of the 16 monkeys that were inoculated.
The US scientists say they now want to use a similar approach to test a vaccine for HIV in humans.
Prof Louis Picker, from the Vaccine and Gene Therapy Institute at Oregon Health and Science University, said: "It's always tough to claim eradication - there could always be a cell which we didn't analyse that has the virus in it. But for the most part, with very stringent criteria... there was no virus left in the body of these monkeys."
Search and destroy
The research team looked at an aggressive form of virus called SIVmac239, which is up to 100 times more deadly than HIV.
Infected monkeys usually die within two years, but in some inoculated primates the virus did not take hold.
Continue reading the main story
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Start Quote
It maintains an armed force, that patrols all the tissues of the body, all the time, indefinitely”
Prof Louis Picker
Oregon Health and Science University
The vaccine is based on another virus called cytomegalovirus (CMV), which belongs to the herpes family.
It used the infectious power of CMV to sweep throughout the body. But instead of causing disease, it has been modified to spur the immune system into action to fight off the SIV molecules.
"It maintains an armed force, that patrols all the tissues of the body, all the time, indefinitely," explained Prof Picker.
The researchers gave rhesus macaque monkeys the vaccine, and then exposed them to SIV.
They found that at first the infection began to establish and spread. But then the monkeys' bodies started to respond, searching out and destroying all signs of the virus.
Of the monkeys that successfully responded to the vaccine, they were still clear of infection between one-and-a-half and three years later.
Prof Picker said his team was still trying to work out why the vaccination worked in only about half of the monkeys.
"It could be the fact that SIV is so pathogenic that this is the best you are ever going to get.
"There is a battle going on, and half the time the vaccine wins and half the time it doesn't," he said.
Human trials
The researchers are now testing the vaccine to see if it can be used after SIV exposure to treat and potentially cure infected monkeys.
They also want to see if the technique could work in humans.
Prof Picker said: "In order to make a human version we have to make sure it is absolutely safe.
"We have now engineered a CMV virus which generates the same immune response but has been attenuated [modified to lose its virulence] to the point where we think it is unequivocally safe."
This would first have to pass through the regulatory authorities, but if it does, he said he hoped to start the first clinical trials in humans in the next two years.
Commenting on the research, Dr Andrew Freedman, from Cardiff University School of Medicine, said: "This suggests that prophylactic vaccines - vaccines designed to prevent infection - using CMV vectors may be a promising approach for HIV.
"While they may not prevent the initial infection, they might lead to subsequent clearance, rather than the establishment of chronic infection."
http://www.bbc.co.uk/news/science-environment-24051860
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Thanks for posting this! I remember reading about this a couple of years ago ... where was that article... ah, here it is! Juicy bits...
"Currently, Picker’s team has no plans to move the vaccine into human studies because of safety concerns about CMV. The virus causes no harm in healthy people and is widespread, infecting nearly half of the U.S. population and more than 90% of people in sub-Saharan African and India. Still, it can hurt fetuses, leading to vision and hearing loss as well as mental retardation, and, in an ironic twist, can cause blindness in immune-deficient children and adults who have diseases like HIV infection. Picker’s group is now trying to make a weakened CMV that cannot cause disease under any circumstance. “We’re fairly far along on it,” he says. “But we’re going to have to prove that it’s safe and still protective.”
http://news.sciencemag.org/2011/05/unusual-aids-vaccine-shows-promising-results-monkeys
Sounds like he's created virus that he thinks is weakened but still effective. Really cool!
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Any thoughts on this?? http://www.wafb.com/story/23407485/aids-vaccine-created-at-ohsu-may-clear-virus-from-body?utm_source=buffer&utm_campaign=Buffer&utm_content=buffere14cd&utm_medium=facebook
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http://forums.poz.com/index.php?topic=48732.msg589648#msg589648
"Happy Hour? A preventive/therapeutic HIV vaccine..."
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Sounds interesting, maybe one to watch.
Here's a longer video (Dr. Picker explaining everything)
http://vimeo.com/74216971
Source:
http://www.ohsu.edu/xd/about/news_events/news/2013/09-11-ohsu-vaccine-candidate-a.cfm
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We might want to merge these threads into one.
Here's the other:
http://forums.poz.com/index.php?topic=50438.0
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Sounds interesting, maybe one to watch.
Here's a longer video (Dr. Picker explaining everything)
http://vimeo.com/74216971
Source:
http://www.ohsu.edu/xd/about/news_events/news/2013/09-11-ohsu-vaccine-candidate-a.cfm
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This is a great news!!
The article below is similar to what OP has posted.
http://www.cbsnews.com/8301-204_162-57602655/vaccine-cures-hiv-like-virus-in-monkeys/
Researchers are saying they might start a Human Trial in next 2 years.
Thanks to those researchers who had been working hard to make this happen..
wow...I wonder what would that mean to us HIVers:).....Good stuff..
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I wonder what would that mean to us HIVers:)
The commentary / speculation by Dr. Steven Deeks in the attached article might offer some perspective:
"The team should take extra precautions when developing a vaccine based on CMV for humans, since the herpes virus is still live, said Dr. Steven Deeks, a clinical researcher at UC San Francisco who wasn’t involved in the study. “We may end up exchanging one virus for another,” he said.
But if all goes well, the vaccine “might have a major impact on the global epidemic,” Deeks said. Current antiretroviral therapies vastly diminish HIV but don’t eradicate it, he said. They can also be expensive, and patients need to take them every day for the rest of their lives.
“In theory, we can give them a CMV vaccine engineered to attack HIV, and they’re cured,” Deeks said."
http://www.latimes.com/science/sciencenow/la-sci-sn-siv-vaccine-clears-virus-hiv-20130911,0,4514986.story
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This seems to be the most detailed article on this approach. It came out today in the NYT. Sure is getting the attention of some of the heavy hitters in HIV. Quite a few questions remain though.
http://www.nytimes.com/2013/09/17/science/new-hope-for-hiv-vaccine.html?_r=0
New Hope for H.I.V. Vaccine
By DONALD G. McNEIL Jr.
Published: September 16, 2013
“Kafkaesque” is not a word normally used to describe immune responses, but it’s how Dr. Louis J. Picker described what his experimental vaccine did to his rhesus monkeys: “It’s like their T-cells were turned into the East German secret police, hunting down infected cells until there were none left.”
Recent work by Dr. Picker, a vaccine expert at Oregon Health & Science University, has shaken up the long, frustrating search for an AIDS vaccine. His latest study, published in Nature last week, has scientists scratching their heads, wondering if it might open up a new avenue for research.
Dr. Picker tested his vaccine in 16 monkeys who were then infected with simian immunodeficiency virus, a close relative of H.I.V., which normally would have sent them spiraling rapidly down to a miserable death. The experimental vaccine protected only nine of them, but it also did something never seen before: these monkeys slowly “cleared” the virus and now appear to be cured. “Three years later, you can’t tell them from other monkeys,” Dr. Picker said.
Dr. Anthony S. Fauci, the head of the National Institute for Allergy and Infectious Diseases, said the effect was “unique.”
And Dr. Barton F. Haynes, the director of the Human Vaccine Institute at Duke University’s medical school, said it was “potentially extremely important to understand how this happened.”
Scientists often test ideas for potential AIDS vaccines by creating similar ones against S.I.V. Never before has one eliminated an existing infection. In that sense, the effect of Dr. Picker’s vaccine was less like that of a measles or flu shot and more like that of the AIDS cures used in two famous cases, known as the Berlin patient and the Mississippi baby.
The Berlin patient, Timothy Ray Brown, was infected with H.I.V. and cured only by obliterating his immune system to defeat his leukemia, and then injecting bone marrow from a donor with a rare H.I.V.-blocking mutation. The unidentified baby was born to an infected mother in Mississippi and apparently infected with H.I.V., but then cured with early and large doses of antiretroviral drugs.
Both now appear to have no H.I.V. lurking deep in their bodies, but it is impossible to be sure because not every bit of their tissue can be tested.
Because he works with monkeys, Dr. Picker was able to do something that would be unthinkable with human patients — necropsy them, grind up every organ and take 240 samples from each to be sure that they harbored no hidden virus.
Making vaccines by simply weakening the virus that causes AIDS has failed because the virus mutates a hundred times faster than even the fast-mutating flu virus. In Dr. Picker’s vaccine, S.I.V. genes are fused to those of another virus, the cytomegalovirus. (The name means “big cell,” and it is in the herpes family but different from its relatives that cause lip and genital sores, chickenpox and shingles.)
H.I.V. fusion has been tried with adenoviruses and others, but cytomegalovirus seems to work better. It’s not entirely clear why, but one theory is that cytomegalovirus has a very long history of infecting primates — so much so that 100 percent of monkeys and about 80 percent of humans get it in their lifetimes.
Therefore, we primates have adapted to it. Although the virus can be lethal to fetuses and to those with immune systems suppressed by AIDS or transplant drugs, in most victims it causes no symptoms.
The body responds to cytomegalovirus more slowly and calmly than it does, for example, to a flu.
As in any infection, the thymus gland generates new white blood cells called T cells — in this case, CD8 hunter-killer cells — primed to target the specific virus. But in the case of Dr. Picker’s vaccine, those cells stay in an unusual “half-alert” state. A full-blown immune response eventually exhausts itself, and can even be dangerous. For example, the rare humans who catch H5N1 bird flu often die of the immune response itself; they drown in the flood of CD8s and other would-be saviors pouring into the lung tissue, spoiling for a fight.
That “half-alert” state is the “Kafkaesque” element: unactivated CD8s wander around aimlessly, while fully activated ones behave like storm troopers. But the half-activated CD8s persist in tissues, eliminating their targets quietly without triggering inflammation or even a mild fever.
When S.I.V. genes are fused to the cytomegalovirus spine, the CD8s kill S.I.V.-infected cells too.
Since it protected only some monkeys, the new technique might be best used in combination approaches. For example, Dr. Fauci said, it could be given with a vaccine that generates antibodies against H.I.V. “and maybe eliminate the cells that sneak past the antibody shield.”
Alternatively, the vaccine might be given to infected patients who are on antiretroviral drugs to see if it can “mop up” lingering reservoirs of virus.
It should take up to three years to get a human version ready for trials, Dr. Picker estimated.
“Now the outstanding question is, ‘Why only half?’ ” said Dr. Mike McCune, an AIDS researcher at the University of California, San Francisco, referring to the monkeys who were protected in Dr. Picker’s trial.
Too often, AIDS advances that work in lots of monkeys don’t work in many humans.
“Not all monkeys are the same,” Dr. McCune said. “They’re not as inbred as mice, but they’re sometimes from the same families, they get the same diets... Who knows what will happen if this goes into humans
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It looks like they're going to move the CMV-based vaccine into human trials --
https://www.dailymail.co.uk/health/article-7257545/Human-trials-HIV-vaccine-start-year.html
Got 59% "clearance" from monkeys with a vaccine which should be safer than their original candidates. I'm not sure if this means that it will have a benefit to those already infected, or it just cleared HIV from those exposed to it after vaccination. Still, it's exciting. I read about the CRISPR and, well, I get worried about off-target effects, such as cancers. This solution relies on CMV which I probably already have. :)