Why is monkey not affected by HIV

HIV research Why some monkeys are immune to AIDS

The soot specification is a small brown-gray monkey from West Africa. Not a very well-known primate species, but alongside the chimpanzee and gorilla it is one of the monkeys that are said to have transmitted the HIV virus to humans. So the soot claim has HIV and can transmit it, but it is itself immune to the disease that HIV can cause in humans: AIDS. Professor Frank Kirchhoff, Director of the Ulm Institute for Molecular Virology explains:

With these monkeys it is the case that they also carry a lot of virus, but the immune system is not constantly activated.

Frank Kirchhoff, Ulm Institute for Molecular Virology

This is crucial, because the virus itself is not the problem with AIDS, but our own immune response to it. The body reacts violently to the virus, which in turn changes at lightning speed. So the body has to react again to the changed variant. A vicious circle:

It's a bit like a marathon where you try to sprint all the time and then of course you don't last long.

Frank Kirchhoff, virologist

In HIV-infected people, the chronic activation of the immune system - for example through bacteria that enter the blood after an infection-related intestinal damage - makes a decisive contribution to the outbreak of AIDS. The immune system breaks down under the strain and can no longer withstand even otherwise harmless diseases such as a cold. However, this does not happen with the soot specification. But why?

To find out, the entire genetic information of these monkeys was deciphered here in order to find genetic differences.

Frank Kirchhoff, virologist

The researchers found a receptor called "TLR4" in the monkey's DNA. This cellular protein plays an important role in the activation of the immune system by bacteria, both in humans and in monkeys. The difference: In the case of the soot information, the receptor is changed and only functions to a lesser extent, in humans it is significantly stronger.

"Using various methods, we were able to prove that the TLR4 receptor of the soot indication has only a low level of activity. This could be the reason why these monkeys do not react with an uncontrolled defense reaction and do not develop an immune deficiency," says Daniel Sauter, junior professor at the Ulm Institute for molecular virology.

In this way, unlike humans, soot can apparently maintain a healthy number of immune cells and tolerate the pathogen for life. The research group also discovered the change in the TLR4 receptor in the green monkey or the Angola colobus. Humans, on the other hand, show a strong immune response to the virus, but this is not effective.

It is known that these monkeys, although they show a weakened immune response against the AIDS-related viruses, are otherwise quite able to cope well with other pathogens. This is due to the fact that the immune system is very versatile and the lack of some functions can in part be replaced by others.

Frank Kirchhoff, virologist

And this is where the therapy of the future could start now: The receptor must also be weakened in humans. Studies are already underway to investigate whether AIDS can be stopped by weakening the immune response to it. With the receptor, however, you now have a clear point of attack. This could then also reduce the side effects of the treatment.