A research published in the journal Nature shows that a vaccine has successfully cleared a monkey version of HIV from the bloodstreams of infected animals.
The research team looked at the SIVmac239 (Simian Immunodeficiency Virus), a form of HIV found in monkeys, which is 100 times more aggressive and tend to kill them within 2 years after being infected.
The vaccine is based on the cytomegalovirus (CMV), which is part of the herpes family. Researchers then used the infectious power of CMV to sweep throughout the body. But instead of causing disease, they modified it to tell the immune system, and particularly the T-cells, to fight off the SIV molecules.
16 monkeys were vaccinated and then exposed to SIVmac239. In nine of the cases, the monkeys’ immune systems were able to fight off infection and destroy the virus. Those monkeys remained SIV free between 1.5 to three years later.
This success leads the US scientists to believe they can use a similar approach to test a vaccine for HIV in humans. Researchers engineered a CMV virus which generates the same immune response but whose virulence has been modified to the point where they 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” one of the research team members, Professor Louis Piker says.
So far, HIV infection has only been cured in a very small number of highly-publicized but unusual clinical cases in which HIV-infected individuals were treated with anti-viral medicines very early after the onset of infection or received a stem cell transplant to combat cancer.
This latest research suggests that certain immune responses obtained by a new vaccine may also have the ability to completely remove HIV from the body.” It could also give support to another research made in Denmark, where scientists are investigating a way to fight off HIV reservoirs thanks to panobinostat, a molecule usually used to treat cancer
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While I applaud OHSU for this innovation, and acknowledge how critical this advance in the endeavor to develop an HIV vaccine, I have some critiques of their work. The first is their decision to utilize CMV as a vector for stimulating the immune system to develop antibodies for prevention of SIV infection. CMV is a member of the herpes virus family. As with all herpes viruses, it remains dormant in the host in an asymptomatic state, meaning that no visible symptoms of infection can be seen. But when CMV infection becomes symptomatic, they become out of hand and uncontrolled. And in the worse case scenario, the symptoms are endless and devastating, and can include impaired functioning in terms of motor ability and speech, and death. While this means does imply CMV is unthreatening as long as it is asymptomatic, one thing that can trigger its pathogenicity and infectiousness is a compromised immune system. And a compromised immune system is the result of HIV and SIV infection. While CMV did not devastate the monkeys used in the vaccine trials, it is important to remember HIV is a much more radical and infectious virus than SIV. In conjunction with CMV, not only could one potentially confer HIV infection, one could also transfer CMV infection and provide an environment conducive to eliciting the worst-case scenario symptoms of CMV infection.
Additionally, if the scientists of OHSU could not measure the viral load of SIV through traditional detection methods, that classifies the infection as undetectable. An undetectable viral load does not mean one is cured of infection. All this means is tests could not show whether the virus was still present in the host or not. The virus could still be inside the tested monkeys, just at very low limits. This is further validated by the fact that one monkey out of the original 9 vaccinated had a resurgence of SIV viral load. While the viral load level was low, this implies the possibility that SIV was still present in that one specimen.
So while I do commend this advance in HIV vaccine development, I am wary to say this is a direct pathway to actually making it a tangible reality. All in all, the main grievance I have is that it gives false hope. This sensationalizes that all the work done up to this point will definitively solve this global crisis, and that it is a goal attainable in the nearby future. The truth is that this work is an important milestone. However, there is still much more work to be done if scientists hope using a CMV vector will have the same effect on HIV in human subjects, as it did with SIV in monkey subjects.
That is a good point actually, having read a bit about the topic, apparently they are first trying to make the CMV viral malignancy to such a low point that it will be considered safe to use during a clinical trials.
Here is what Professor Picker, member of the research group, said for a BBC News article : “In order to make a human version we have to make sure it is absolutely safe. The researchers now want to move from monkeys to test the vaccine in humans “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”
So the humans test for these findings are really not for today or tomorrow but that is still a good breaktrhough.
Maybe we could imagine that one day these findings could be mixed with the ones from the Danish scientists who are currently trying to find how to tackle the “HIV reservoirs” making this disease low enough to be dormant in the patient’s body, but not enough to cure it…
If you want to know more about this other trial here is a link that explains it : http://www.nydailynews.com/life-style/health/early-signs-hiv-cure-promising-danish-scientists-article-1.1329530