Genetic cause of innate resistance to HIV/AIDS

July 16, 2008

Some people may be naturally resistant to infection with HIV, the virus that causes AIDS. The results of a study conducted by Dr. Nicole Bernard of the Research Institute of the McGill University Health Centre (MUHC) bring us closer to a genetic explanation. Her study findings were published on July 16 in the journal AIDS.

The simultaneous expression of certain versions of two specific genes called KIR3DL1 and HLA-B*57 is thought to be at the root of some cases of this innate resistance to HIV infection. Depending on which versions of these two genes the patient has, he or she will resist HIV infection or develop AIDS at a slower rate.

These results were obtained by comparing the genetic profiles of people undergoing primary HIV infection ( in their first year of infection) to those repeatedly exposed to HIV but non-infected. The group of exposed but non-infected patients came from a cohort studied by Dr. Julie Bruneau of the Centre hospitalier de l'Université de Montréal. The cohort of primary HIV infected patients is studied by Dr. Jean-Pierre Routy, from the MUHC. Analyses show that the "good" versions of both genes were present in 12.2% of exposed but non-infected subjects versus only 2.7% in patients in primary HIV infection.

As of yet, no study has clearly described the mechanism of this protection. The KIR3DL1 gene codes for a receptor on the surface of the immune system's natural killer (NK) cells, which when activated destroy infected cells in the body. The HLA-B*57 gene codes for a protein normally found on the surface of all body cells that binds the KIR3DL1 and dampens NK cell activity. The most likely hypothesis is that HIV prevents the HLA-B*57-encoded protein from being expressed on the surface of the infected cells, making it unavailable to bind KIR3DL1. As a consequence, the NK cells retain their activity and destroy the virus-infected cells.

As this mechanism can occur very soon after the virus has started to infect the body cells, people carrying those versions of the 2 genes may be able to destroy more efficiently the infected cells following exposure to HIV, thus lowering their chances of developing AIDS.

"More research is needed to determine the exact mechanism behind the protection we have observed, but these findings have revealed a promising avenue," according to Dr. Bernard.

This study opens the way for new ideas in the fight against HIV infection. "In the future, our findings could be used to somehow 'boost' the innate immune system and thus fight the virus as soon as it enters the body," said Dr. Bernard.

Source: McGill University Health Centre

Explore further: Mutational tug of war over HIV's disease-inducing potential

Related Stories

Mutational tug of war over HIV's disease-inducing potential

August 23, 2016

A study from Emory AIDS researchers shows how the expected disease severity when someone is newly infected by HIV reflects a balance between the virus' invisibility to the host's immune system and its ability to reproduce.

How a nasty, brain-eating parasite could help us fight cancer

August 26, 2016

We've known since the turn of the 20th century that some infectious diseases are a major risk for developing specific cancers. More worryingly, about one-sixth of cancers worldwide are attributable to infectious agents. Globally, ...

Big step towards cure for lifelong viral infections

August 3, 2016

New research has taken us a step closer to finding a cure for human immunodeficiency virus (HIV), as well as other infections including the glandular fever virus, which is associated with the development of lymphoma. Some ...

HIV is not a super-spreader of drug-resistant tuberculosis

August 9, 2016

While the human immunodeficiency virus (HIV) pandemic fuels tuberculosis (TB) outbreaks, it does not drive the development and transmission of multidrug-resistance in TB patients as previously suspected, according to a study ...

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Cow embryos reveal new type of chromosome chimera

May 27, 2016

I've often wondered what happens between the time an egg is fertilized and the time the ball of cells that it becomes nestles into the uterine lining. It's a period that we know very little about, a black box of developmental ...

Shaving time to test antidotes for nerve agents

February 29, 2016

Imagine you wanted to know how much energy it took to bike up a mountain, but couldn't finish the ride to the peak yourself. So, to get the total energy required, you and a team of friends strap energy meters to your bikes ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.