Новини - Категории 'Новини ХИВ/СПИН'

Става ли ХИВ по-малко заразен?

Вирусът на СПИН еволюира в по-малко заразна и смъртоносна инфекция, сочат данните на ново проучване.
На територията на Ботсвана всеки новозаразен с вируса е по-малко вероятно да развие заболяването, в сравнение със случаите на инфектиране преди 20 – 30 години, обяснява съавторът на проучването Филип Голдър – изследовател имунолог от Оксфордския университет в Англия. Според него, ако този процес продължи, ХИВ ще причинява все по-малко заболявания. 
Проучването обаче има и някои уговорки. Учените подчертават, че все пак става дума за данни само от две страни, като и двете са в Африка, и е възможно изводите да не важат за останалата част от света. Някои от откритията са въз основа на математически модели на начина, по който ХИВ еволюира. 
Въпреки това новините са добри, подчертава Голдър, като допълва, че благодарение на естествения подбор, някои вируси еволюират, за да не причиняват гибелта на гостоприемника. 
Той пояснява, че „най-успешните“ патогени са тези, които се развиват до степен, при която причиняват заболяване в по-малка степен. По този начин гостоприемникът живее по-дълго, а те имат възможност да се разпространяват по други организми. 
Източник: Оксфордски университет - Англия

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Публикувана от rosen - петък, 09 януари 2015 - 16:19:02изглед за печат

HIV vaccines should avoid viral target cells, primate model study suggests

Vaccines designed to protect against HIV can backfire and lead to increased rates of infection. This unfortunate effect has been seen in more than one vaccine clinical trial.

Scientists at Yerkes National Primate Research Center, Emory University, have newly published results that support a straightforward explanation for the backfire effect: vaccination may increase the number of immune cells that serve as viral targets. In a nonhuman primate model of HIV transmission, higher levels of viral target cells in gateway mucosal tissues were associated with an increased risk of infection.

The findings, published in Proceedings of the National Academy of Sciences, suggest that vaccine researchers, when evaluating potential HIV/AIDS vaccines, may need to steer away from those that activate too many viral target cells in mucosal tissues.

"One of the reasons why it has been so difficult to make an AIDS vaccine is that the virus infects the very cells of the immune system that any vaccine is supposed to induce," says senior author Guido Silvestri, chief of microbiology and immunology at Yerkes National Primate Research Center.

Silvestri is also a professor of pathology and laboratory medicine at Emory University School of Medicine and a Georgia Research Alliance Eminent Scholar. The first author of the paper is senior research specialist Diane Carnathan, PhD, and colleagues from the Wistar Institute, Inovio Pharmaceuticals and the University of Pennsylvania contributed to the study.

A large part of the HIV/AIDS vaccine effort has been focused on developing vaccines that stimulate antiviral T cells. T cells come in two main categories, defined by the molecules found on their surfaces. CD8 is a marker for "killer" cells, while CD4 is a marker for "helper" cells. CD4+ T cells are known to be primary targets for HIV and SIV (simian immunodeficiency virus) infection, while several studies have proposed that CD8+ T cells could be valuable in controlling infection.

Source: Emory Health Sciences

Публикувана от rosen - петък, 02 януари 2015 - 12:11:07изглед за печат

Molecules seen binding to HIV-1's protective capsule, blocking infection

Imagine a suitcase on a bumpy ride. With enough jostling it opens, spilling clothes everywhere. Similarly awkward, the suitcase locks may jam and not open at the destination.

This analogy illustrates the importance of the protective capsule, called the capsid, which surrounds the HIV-1 genome. (HIV is short for human immunodeficiency virus.) The capsid has to disassemble once the virus enters the cell, releasing its disease-causing cargo at precisely the right time and place.

"It's still a matter of debate at what point the capsid falls apart in HIV-1 infection of cells," said Dmitri Ivanov, Ph.D., assistant professor of biochemistry in the School of Medicine at The University of Texas Health Science Center at San Antonio. Dr. Ivanov is a senior author on a study, published Dec. 15 in Proceedings of the National Academy of Sciences, that offers clues about HIV-1 capsid disassembly.

The paper shows how an HIV-1 inhibitor called PF74 and a host protein called CPSF6 bind to a small pocket on the surface of the capsid and prevent it from disassembling. The suitcase, if you will, is locked. Viral information is kept inside.

"We think that this process can be targeted for therapeutic purposes in HIV-1 infections," Dr. Ivanov said.

In part of the study, researchers used X-ray crystallography at the UT Health Science Center to visualize the three-dimensional structure of the CPSF6 protein bound to the HIV-1 capsid.

"Seeing molecules in 3-D is illuminating; it tells us something about their function," Dr. Ivanov said. "We now know how PF74 and CPSF6 interact with the adjacent building blocks of the HIV-1 capsid, thus stabilizing the entire capsid structure. It tells us that these molecules bind to the capsid before disassembly, blocking viral replication."

Source: University of Texas Health Science Center at San Antonio

Публикувана от rosen - вторник, 30 декември 2014 - 11:49:39изглед за печат

Statement on incident involving GALZ members in Zimbabwe

The International HIV/AIDS Alliance today expressed extreme concern at reports that members of its partner organisation in Zimbabwe, Gays and Lesbians of Zimbabwe (GALZ), were reportedly attacked and injured at a private event on Friday.

GALZ is a membership-based organisation serving the needs and interests of lesbian, gay, bisexual, transgender and intersex (LGBTI) persons in Zimbabwe, pushing for social tolerance of sexual minorities.  It is thought that some 35 GALZ members needed medical treatment  following the attack.

The rise in violence against vulnerable people in Zimbabwe, including against the LGBTI community and women, has negative implications for human rights, health and HIV in the country. The adverse legal environment, where most at risk groups face living in a climate of fear and are criminalised for their behaviour, not only makes them a target for harassment and violence but also creates a vacuum when it comes to the provision of healthcare and support services for all minority groups.

Gavin Reid, the Alliance’s Regional Advisor on Men's Sexual Health & Rights for East and Southern Africa said: “The International HIV/AIDS Alliance calls upon the Zimbabwean police to investigate the incident and bring the perpetrators to justice.  It’s the duty of the Zimbabwean government to protect and promote the rights of all its citizens and to ensure that all Zimbabweans are able to enjoy their full constitutional rights including the right to life, to personal security, to freedom of assembly and association, and to freedom from torture.”

Since 2012, GALZ has been a partner in SHARP – a Men’s Sexual Health and Rights Programme being implemented by the International HIV/AIDS Alliance and its implementing partners in Zimbabwe, Kenya, Tanzania and Uganda. The programme aims to effectively reduce the spread and impact of HIV among men who have sex with men (MSM) and to build healthy MSM communities in the region.

Source: http://www.aidsalliance.org/

Публикувана от rosen - понеделник, 22 декември 2014 - 11:44:00изглед за печат

How llamas' unusual antibodies might help in the fight against HIV/AIDS

Most vaccines work by inducing an immune response characterized by neutralizing antibodies against the respective pathogen. An effective HIV vaccine has remained elusive so far, but researchers have continued to make progress, often employing innovative methods. A new study reports that a combination of antibodies from llamas can neutralize a wide range of circulating HIV viruses.

After initial disappointment that HIV vaccine candidates were unable to elicit neutralizing antibodies, researchers found that some HIV-infected individuals did produce such antibodies. The current challenge is therefore to find safe and effective vaccine formulations (as opposed to HIV infection) that trigger the development of neutralizing antibodies that can recognize and prevent infection with all or most circulating HIV subtypes.

Many known neutralizing antibodies are directed against a specific part of the virus that binds to the CD4 receptor on the human target cells, and structural biology studies indicated that the site is a narrow groove. Antibodies in most mammals are relatively large proteins made up of two copies of two different individual parts (or chains), and bulkiness might be one reason why neutralizing antibodies are rare. Llamas are a notable exception: besides the common four-chain antibodies they also produce smaller ones made up of only two of the four chains. Robin Weiss, an HIV expert, and Theo Verrips, a llama antibody expert, therefore started working with this unconventional research animal.

Laura McCoy (working with Weiss at University College London, UK) led an international group of researchers to test immunization protocols and the resulting immune response in llamas. Having previously identified one particular HIV neutralizing llama antibody, for this study the researchers immunized two additional llamas and identified a total of three new neutralizing antibodies. The four HIV neutralizing llama antibodies target different parts of the CD4-binding site of the virus, and the researchers could show that when used in combination, rather than interfering with each other, they are more potent and can neutralize all of the 60 different HIV strains tested.

Source: PLOS Pathogens

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Публикувана от rosen - четвъртък, 18 декември 2014 - 11:34:51изглед за печат
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