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Michael2901
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Re: Interesting news articles about AIDS

This link gives more information about this latest anti-HIV drug Edurant (rilpivirine, RPV, TMC-278). Unfortunately (like most medications for almost any illness) it does appear to have some potentially difficult side effects...

http://www.aidsmeds.com/archive/Edurant_1619.shtml
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Papa3
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Re: Interesting news articles about AIDS

http://www.sciencecodex.com/sivresistant_monk..._gates_to_viral_infection

[...] To infect a cell, HIV and SIV need to find two molecules on the cell's surface. Scientists call these molecules co-receptors, and they can be thought of as gates. One of the co-receptors is CD4, which appears on immune cells called T cells. The other is called CCR5. Stimulating a T cell usually increases the level of CCR5, facilitating infection.

Paiardini, Cervasi and their colleagues found that in sooty mangabey [monkey]s, a type of T cell called a central memory T cell doesn't turn on CCR5. This means that even when a sooty mangabey is infected with SIV, some T cells can mostly avoid being killed by the virus. [...]

"For several years, we and others thought lack of chronic immune activation was the main factor protecting sooty mangabeys from AIDS," Paiardini says. "This study changes this working model and proposes that lack of immune activation in sooty mangabey is secondary, deriving from their ability to protect and maintain their central memory T cells." [...]
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l_mckeon
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Re: Interesting news articles about AIDS

http://www.abc.net.au/rn/scienceshow/stories/2011/3243359.htm has a new approach to preventing HIV infection of uncircumcised males in Africa.
(Select transcript -- relevant part is about 70% down the article).

Basically, It's thought female HRT cream applied to male foreskin once a week keratinizes the foreskin, making it impervious to the virus.
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Papa3
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Re: Interesting news articles about AIDS

http://www.sciencecodex.com/case_western_rese...y_hivinhibiting_mechanism

[...] Researchers at Case Western Reserve University School of Medicine have discovered a long-sought cellular factor that works to inhibit HIV infection of myeloid cells, a subset of white blood cells that display antigens and hence are important for the body's immune response against viruses and other pathogens. The factor, a protein called SAMHD1, is part of the nucleic acid sensing machinery within the body's own immune system. It keeps cells from activating immune responses to the cells own nucleic acids, thus preventing certain forms of autoimmunity from developing. [It] can also sense and interfere with infection of myeloid cells, such as macrophages and dendritic cells, with HIV-1 and related immunodeficiency viruses. As such, SAMHD1 prevents the synthesis of virus copies in these cells [...] in addition to preventing inappropriate autoimmune responses such as those seen in [Acairdi-Goutieres syndrome], SAMHD1 possesses the ability to inhibit infection of myeloid cells by HIV by effectively interfering with the production of viral nucleic acids. Through this action SAMHD1 may prevent efficient activation of immune responses to HIV-1 virus in infected individuals, Dr. Skowronski explains.
The research also shows HIV-2 and related simian immunodeficiency viruses (SIVsm/mac) are able to overcome the protective mechanism within myeloid cells by using the protein Vpx they encode, to dispose of SAMHD1, thereby allowing infection with these viruses. Interestingly, viruses possessing Vpx, such as HIV-2, are much less pathogenic than HIV-1. This could be because by being able to establish infection in myeloid cells they provoke much more robust immune responses that HIV-1 does, since HIV-1 can not infect these cells efficiently [...] As a result, "One might expect that manipulation of SAMHD1 function in the context of HIV-1 infection may lead to more robust immune response to this virus" according to Dr. Skowronski. Moving forward, researchers will focus on better understanding the molecular pathway SAMHD1 uses to inhibit HIV-1 infection. They will likewise strive to learn more about how SAMHD1 shapes the development of AIDS in HIV-infected individuals [...]
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Michael2901
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Re: Interesting news articles about AIDS

http://www.medicalnewstoday.com/releases/229932.php

"Article Date: 29 Jun 2011

The Blood-Brain Barrier Disrupted By HIV

HIV weakens the blood-brain barrier - a network of blood vessels that keeps potentially harmful chemicals and toxins out of the brain - by overtaking a small group of supporting brain cells, according to a new study in the June 29 issue of The Journal of Neuroscience. The findings may help explain why some people living with HIV experience neurological complications, despite the benefits of modern drug regimens that keep them living longer..."
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Dan60
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Re: Interesting news articles about AIDS

Protease inhibitor drugs are one of the major weapons in the fight against HIV, the virus that causes AIDS, but their effectiveness is limited as the virus mutates and develops resistance to the drugs over time. Now a new tool has been developed to help predict the location of the mutations that lead to drug resistance.

http://www.physorg.com/news/2011-07-entry-prohibited-aids-viruses-peptide.html
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Re: Interesting news articles about AIDS

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Dan60
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Re: Interesting news articles about AIDS

Dan60, thanks for the link!
SekeRob, thanks, point taken. You are absolutely right, these particular articles are not related to the topic. Although the presented approach looks valid for HIV also. First article confirms that antivirals can be delivered across the blood/brain barrier (and as far as I can remember last year research confirmed HIV presence in the brain). Second article is about application of physical laws in medical domain which to me is also a new field of research, and in practice meaning that if there is a way to identify a latent cell (let's suppose a flag-protein), then it can be targeted with a complex of binding mechanism + nanoparticle. After that the same heating mechanism can be applied, destroying the cell and the virus since the temperature used for cancer is above HIV threshold.

Question: I can not find any studies on when HIV enters latency. Are you aware of any? If so, can you share a link? Does it happens after the infection or only when HAART is started? The point in asking is to understand is it a logical protection mechanism of the virus (absence of free-floating virus achieved by antivirals pushes HIV to go into the latency stage, change in infected person temperature, or even presence of the antibodies) or is it the virus unlogical nature that sometimes just "prefers" latency to multiplication opportunity? Will the presence of the virus in blood (or something mimicking the virus) bring it back to its active lifecycle?


Hi Drewer, that's me again. I've just found a very interesting website all about "latency" and "reservoir cells" and I thought you (and others) might like to take a look at it: http://www.hiv-reservoir.net/

Regards.
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Papa3
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Re: Interesting news articles about AIDS

http://www.sciencecodex.com/caltech_researche...y_of_hivbattling_proteins

Caltech researchers increase the potency of HIV-battling proteins
Posted On: July 29, 2011 - 1:30pm

[...] The protein, called cyanovirin-N (CV-N), is produced by a type of blue-green algae and has gained attention for its ability to ward off several diseases caused by viruses, including HIV and influenza. [...] "By linking two cyanovirins, we were able to make significantly more potent HIV-fighting molecules," says Jennifer Keeffe, a staff scientist at Caltech and first author of a new paper describing the study in the Proceedings of the National Academy of Sciences (PNAS). "One of our linked molecules was 18 times more effective at preventing infection than the naturally occurring, single protein."
The team's linked pairs, or dimers, were able to neutralize all 33 subtypes of HIV that they were tested against. The researchers also found the most successful dimer to be similar or more potent than seven well-studied anti-HIV antibodies that are known to be broadly neutralizing.
CV-N binds well to certain carbohydrates, such as the kind found in high quantities connected to the proteins on the envelope that surrounds the HIV virus. Once attached, CV-N prevents a virus from infecting cells, although the mechanism by which it accomplishes this is not well understood.
What is known is that each CV-N protein has two binding sites where it can bind to a carbohydrate and that both sites are needed to neutralize HIV.
Once the Caltech researchers had linked two CV-Ns together, they wanted to know if the enhanced ability of their engineered dimers to ward off HIV was related to the availability of additional binding sites. So they engineered another version of the dimers—this time with one or more of the binding sites knocked out—and tested their ability to neutralize HIV.
It turns out that the dimers' infection-fighting potency increased with each additional binding site—three sites are better than two, and four are better than three. The advantages seemed to stop at four sites, however [...] Although CV-N has a naturally occurring dimeric form, it isn't stable at physiological temperatures, and thus mainly exists in single-copy form. To create dimers that would be stable under such conditions, the researchers covalently bound together two CV-N molecules in a head-to-tail fashion, using flexible polypeptide linkers of varying lengths.
Interestingly, by stabilizing the dimers and locking them into a particular configuration, it seems that the group created proteins with distances between binding sites that are very similar to those between the carbohydrate binding sites in a broadly neutralizing anti-HIV antibody.
"It is possible that we have created a dimer that has its carbohydrate binding sites optimally positioned to block infection," says Stephen Mayo, Bren Professor of Biology and Chemistry, chair of the Division of Biology, and corresponding author of the new paper.
Because it is active against multiple disease-causing viruses, including multiple strains of HIV, CV-N holds unique promise for development as a drug therapy. Other research groups have already started investigating its potential application in prophylactic gels and suppositories.
"Our hope is that those who are working to make prophylactic treatments using cyanovirin will see our results and will use CVN2L0 instead of naturally occurring cyanovirin," Keeffe says. "It has higher potency and may be more protective."
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Dan60
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Re: Interesting news articles about AIDS

Molecular cut and paste


"...A classic arms-race situation has developed, wherein TRIM5 has tried to maintain its ability to recognize the rapidly evolving retroviruses, placing the gene under some of the strongest Darwinian selection in the entire primate genome. However, HIV-1 seems to have the upper hand at the moment: the human TRIM5 variant only marginally reduces the replication of HIV-1. Could this be one of the failures in human immunity that has permitted such a dramatic invasion by this pathogen? And what does human TRIM5 need to do in order to gain the upper hand? Or, to ask a bolder question, what can we do to it to engineer resistance to the disease?"


"A combination of cheap DNA synthesis, freely accessible databases, and our ever-expanding knowledge of protein science is conspiring to permit a revolution in creating powerful molecular tools, suggests William McEwan, Ph.D., a virologist at the MRC Laboratory of Molecular Biology, Cambridge, U.K., in this excerpt from the new book Future Science: Essays From The Cutting Edge, edited by Max Brockman."

http://www.kurzweilai.net/molecular-cut-and-paste
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