SIV surrenders. A monkey test of a new AIDS vaccine defeated a powerful strain of the simian version of HIV.
Credit: Fotosearch
Posted on 05/13/2011 8:54:49 AM PDT by neverdem
A new study gives a much-needed booster shot to the beleaguered AIDS vaccine field. The experiment, led by immunologist and pathologist Louis Picker of the Oregon Health & Science University in Beaverton, showed that an unusual approach to vaccinating against SIV (a simian cousin of HIV) protected 12 of 24 monkeys from a “challenge” with a particularly virulent strain of that virus. Specifically, all monkeys became infected, but in half of the animals, their immune systems drove the virus down to undetectable levels for more than a year.
“It’s the best result I’ve seen against the worst SIV known,” says the University of Wisconsin’s David Watkins, an immunologist who tests AIDS vaccines in monkeys and was not involved with the work. “I’m very excited by this approach.”
The vaccine contains SIV genes stitched into cytomegalovirus (CMV), a herpesvirus that harmlessly infects many humans and serves as the delivery vehicle, or vector, for the AIDS virus proteins. Typically, AIDS vaccines use vectors that quickly die, but CMV stays alive indefinitely and constantly confronts the immune system with the mock version of the enemy. As a result, Picker contends, the immune system stays on high alert and can respond to an attack by SIV much more quickly. “The whole game changes when you talk about early interception of the virus,” he says.
AIDS researchers have long debated which specific immune responses correlate with protection, and this study—published online today in Nature—is reigniting that discussion. Picker contends that a novel type of T cell response plays a critical role in why the vaccine works, but others find the evidence for that less than compelling. “I’m not sure what the protective mechanism is in these experiments,” Watkins says.
Most vector-based AIDS vaccines train what are known as central memory T cells to recognize the virus. Upon a real infection, these cells expand and mount an attack. But, Picker says, “it’s too late and too little to handle [AIDS] viruses.” With the CMV vector, monkeys developed high levels of so-called effector memory T cells, which do not go through an expansion phase and remain ready to do battle at all times. Other experiments suggested that these cells were key and that only CMV rouses them. Picker’s team vaccinated monkeys with a variety of vectors bearing SIV genes, but none of them triggered effector memory cells. Monkeys receiving these other vaccines and challenged with the same highly pathogenic SIV (known as mac239) handled the virus little better than control animals that did not receive any vaccine. “Our vaccine is completely different than all the other vaccines and works completely differently,” Picker says.
Picker suspects that the monkeys that received CMV vaccines but failed to control the challenge virus did not generate high enough levels of effector memory cells in their tissues. He’s looking for ways to augment the effector memory response and would like to combine the CMV vaccine with one that elicits antibodies against SIV and, ultimately, HIV.
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.”
Sales of gay monkeys set to go through the roof...
$50 billion in research and study and NO cure. Let’s focus our research on cancer and other un-popular, un-pc disease instead shall we?
Next on then ticket will be a Bill to permit marriages with chimpanzees.
Cancer cures are not “sex positive”,
therefore, the left and their god, the government, won’t prioritize them over alleviating the consequences (Rom 1:27 “Men committed indecent acts with other men, and received in themselves the due penalty for their perversion. “) of homosexual acts.
Do you have a source for that price tag? There's no cure, but there's been a lot of basic immunology and virology that's been learned.
Let’s focus our research on cancer and other un-popular, un-pc disease instead shall we?
There are over two hundred different kinds of cells in the human body. There's very little in common among them when they become malignant except they had undergone various and sundry changes in their genes.
If this line of research using a vaccine based on effector memory T cells pans out, it could obviate the very costly highly active antiretroviral therapy, HAART, drugs.
When you allow folks with a communicable, incurable disease to wander freely in the population, you are asking for trouble.
As usual, Cuba's quarantine of its HIV/AIDS population gets a pass from the left.
As usual, Cuba’s quarantine of its HIV/AIDS population gets a pass from the left.
Thus showing that the homos are only a convenient weapon for advancing the cause of Marxism. If the homo agenda didn’t serve to destroy the enemies of the Marxist expansion, they’d be tossed under the bus (as they are in Cuba).
Good point! I can't take the left's hypocrisy any more. That's another reason we don't need any milktoast RINO for the GOP nomination. We need a firebreathing conservative that will take that "red state" appelation and give it back to the pinkos and commies where it belongs, all the while smiling along the way.
It’s good to point out their hypocrisy,
then once this hypocrisy is exposed, then you propose that, indeed, maybe they AREN’T hypocrites...
They are true to their REAL belief system - the advancement of the Marxist/communist agenda. They are ENTIRELY CONSISTENT when it comes to that agenda.
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FReepmail me if you want on or off my health and science ping list.
CMV is harmless? The Red Cross vampires told me my blood was preferred for infants because I was CMV negative, a minority condition in adults.
For most people with normal immune systems. I saw a bad case of mononucleosis from CMV which is usually caused by its cousin in the Herpes family, Epstein-Barr.
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