Scientists in the U.S. and France found that some cells in the body can repel the attack of the HIV virus: depriving the virus of the components you need to live.

Viruses can not reproduce themselves, they need to “hijack” other cells to convert their production facilities and launch their infection.


Now a study published in Nature Immunology, showed how some parts of the immune system destroys its own raw materials to avoid the attack of HIV.

Scientists warn, however, still do not know if this finding can be moved to a therapy.
HIV works by attacking the immune system and weakens the body’s defenses so that any infection becomes fatal to the patient.

However, not all of the immune system “pays” to the virus.

Some cells, macrophages and dendrite cells, which play an important role in organizing the immune system, appear to be more resistant to attack.

Last year the same team of scientists identified a protein, called SAMHD1, which is a crucial part of this resistance.

Now scientists say they discovered how this protein.

The study showed that undoes SAMHD1-essential components or raw material-DNA.
When a cell needs to make a copy of itself draws on a reservoir of these components, called dNTP.

However, these materials can also be used by the virus to reproduce.

Raw material

The research, conducted at the Medical Center of the University of Rochester, Langone Medical Center, University of New York and several institutions in France, found that SAMHD1 did decrease the amount of dNTP to levels below those needed to produce viral DNA.

“Macrophages literally eat the harmful organisms and do not want these organizations have at their disposal the cellular machinery needed to replicate”

Prof Baek Kim

And so the protein prevented virus infection.

When the SAMHD1 scientists removed from the cells, and they had higher levels of dNTP, were infected with HIV.

“By reducing the pool of dNTPs available, SAMHD1 virus effectively deprived the raw material is essential for its replication strategy,” say the authors.

It is possible that macrophages and dendritic cells produce SAMHD1 because they are the “mature cells” which do not require new cells replicate.

Professor Baek Kim, one of the researchers, says that “it makes sense that a mechanism would be the one to activate the macrophages.”

“Macrophages literally eat the harmful organisms and do not want these organizations have at their disposal the cellular machinery needed to replicate.”

“The macrophages themselves do not need that equipment because they do not play.”

“So have SAMHD1 macrophages to get rid of the raw material such dangerous organisms need to copy themselves. It’s a great defense,” adds the scientist.

Dr Jonathan Stoye, a virologist at the National Institute for Medical Research Medical Research Council UK, was part of the team that determined the chemical structure of the SAMHD1 last year and predicted that the protein can attack the dNTP.

The scientist says that “we think that this mechanism worked well and this study confirms that we were right.”

“The SAMHD1 deprives cells of the raw material of dNTP in cells that are not dividing.”

“However, some cells replicate themselves need to increase in number as part of an immune defense. For example CD4 cells, which is the primary target of HIV infection?”

“The cells that are replicating would be in trouble if they are deprived of the dNTP” said Dr. Stoye.

He adds that “we have no very cleared how we can use the strategy of this antiviral protein.”