New compound may disrupt HIV’s hijacking of immune system
Last Updated: Tuesday, February 14, 2012, 14:02
  

Washington: Researchers are testing a promising compound that may counteract HIV’s ability to hijack the immune system’s protection mechanism.

One of the frustrations for scientists working on HIV/AIDS treatments has been the human immunodeficiency virus’ ability to evade the body’s immune system.

Now an Indiana University researcher has discovered a compound that could help put the immune system back in the hunt.

It’s not that the human immune system doesn’t recognize HIV. Indeed, an infection causes the body to unleash antibodies that attack the virus, and initially some HIV is destroyed.

But HIV is able to quickly defend itself by co-opting a part of the innate human immune system — the immune system people are born with, called the complement.

The complement includes a vital mechanism that prevents immune system cells from attacking the body’s own cells. HIV is able to incorporate a key protein in that self-protection mechanism, CD59, and by doing so makes itself appear to be one of the body’s normal cells, not an infective agent.

“HIV is very clever. As it replicates inside cells, it takes on the CD59. The virus is covered with CD59, so the immune system treats the virus like your own normal cells,” Dr. Andy Qigui Yu, M.D., Ph.D., assistant professor of microbiology and immunology said.

“If we find that mechanism, then we can develop something to block that incorporation, and HIV may lose that protection from the immune system,” Dr. Yu said.

Researchers have been able in the past to generate antibodies that successfully attacked HIV in the laboratory.

But these antibodies have failed in human testing because the virus in the body escapes from immune system attacks, Dr. Yu said.

In an attempt to disrupt HIV’s hijacking of CD59, Yu and colleagues at IU and Harvard University crafted a molecule from a bacterial toxin that is known to bind to the CD59 protein.

In laboratory tests, they administered the molecule to blood samples taken from patients with HIV. The bacteria toxin molecule latched on to the CD59 proteins, revealing the viral particles to be invaders and enabling the antibodies to attack the virus.

The researchers suggested that the molecule could potentially be developed into a new therapy to fight HIV/AIDS.

More recent experiments have indicated that the administration of the molecule enabled the antibody-complement to attack infected cells and not just the virus particles found in the blood samples.

The next steps will include more extensive testing of the molecule in a broader range of patient samples, Dr. Yu said.

The study has been published in the Journal of Immunology.

ANI


First Published: Tuesday, February 14, 2012, 14:00



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