Home  |  Top News  |  Most Popular  |  Video  |  Multimedia  |  News Feeds  |  Feedback
  Medicine  |  Nature & Earth  |  Biology  |  Technology & Engineering  |  Space & Planetary  |  Psychology  |  Physics & Chemistry  |  Economics  |  Archaeology
Top > Medicine, Health Care > New Research Reveals How Protein… >

New Research Reveals How Protein Protects Cells from HIV Infection

Published: February 13, 2012.
Released by NYU Langone Medical Center / New York University School of Medicine  

A novel discovery by researchers at NYU Langone Medical Center and colleagues reveals a mechanism by which the immune system tries to halt the spread of HIV. Harnessing this mechanism may open up new paths for therapeutic research aimed at slowing the virus' progression to AIDS. The study appears online ahead of print today in Nature Immunology.

"A lot of research on viruses, especially HIV, is aimed at trying to understand what the body's mechanisms of resistance are and then to understand how the virus has gotten around these mechanisms," said co-lead investigator Nathaniel R. Landau, PhD, a professor of microbiology at the Joan and Joel Smilow Research Center at NYU School of Medicine.

The research focused on a protein called SAMHD1. Recent studies have found that immune cells, called dendritic cells, containing the protein are resistant to infection by HIV. Since the discovery, scientists have sought to understand how SAMHD1 works to protect these cells, with hopes that science might find a way to synthetically apply that protection to other cells.

Dr. Landau and his team are now able to provide an answer:

When a virus, like HIV, infects a cell, it hijacks the cell's molecular material to replicate. That molecular material is in the form of deoxynucleotide triphosphates (dNTPs), which are the building blocks for DNA. Once the virus replicates, the resulting DNA molecule contains all the genes of the virus and instructs the cell to make more virus.

Researchers wanted to understand how cells containing the SAMHD1 protein are protected from such hijacking. They found that SAMHD1 protects the cell from viruses by destroying the pool of dNTPs, leaving the virus without any building blocks to make its genetic information – a process researchers call nucleotide pool depletion. "SAMHD1 essentially starves the virus," Dr. Landau said. "The virus enters the cell and then nothing happens. It has nothing to build and replicate with, so no DNA is made."

As a result, the most common form of HIV does not readily infect these cells. Instead, the virus has evolved to replicate mainly in a different kind of cell, called CD4 T-cells, which do not contain SAMHD1 and therefore have a healthy pool of dNTPs. Dr. Landau explained that the virus has evolved in such a way that it may deliberately avoid trying to infect immune cells with SAMHD1 to avoid alerting the greater immune system to activate a variety of antiviral mechanisms to attack the virus. Viruses that are related to HIV, like HIV-2 and SIV, have developed a protein called viral protein X (VPX) that directly attacks SAMHD1. This allows the virus to infect dendritic cells, an important type of immune cell.

"Viruses are remarkably clever about evading our immune defenses," Dr. Landau said. "They can evolve quickly and have developed ways to get around the systems we naturally have in place to protect us. It's a bit of evolutionary warfare and the viruses, unfortunately, usually win. We want to understand how the enemy fights so that we can outsmart it in the end."

Understanding the mechanism by which SAMHD1 provides protection to cells may provide a new idea about how to stop or slow the virus' ability to spread, Dr. Landau explained. Potential future research efforts, for example, might focus on finding a way to increase the amount of SAMHD1 in cells where it does not exist, or to reduce the amount of dNTPs in cells vulnerable to infection.

"Over the past few years, a number of these natural resistance mechanisms have been identified, specifically in HIV, but some have potential applications to other viruses, as well," he said. "This is a very exciting time in HIV research. Many of the virus' secrets are being revealed through molecular biology, and we're learning a tremendous amount about how our immune system works through the study of HIV."




The above story is based on materials provided by NYU Langone Medical Center / New York University School of Medicine.

Translate this page: Chinese French German Italian Japanese Korean Portuguese Russian Spanish


comments powered by Disqus


Related »

Pennsylvania 
12/9/11 
★★★★ 
Changing the Locks: HIV Discovery Could Allow Scientists to Block Virus's Entry into Cell Nucleus
Scientists have found the 'key' that HIV uses to enter our cells' nuclei, allowing it to disable the immune system and cause AIDS The finding, published today in the …
Hiv 
4/29/10 
New HIV Model Suggests Killer T Cell for Vaccine
Limited success in modelling the behaviour of the complex, unusual and unpredictable HIV virus has slowed efforts to develop an effective vaccine to prevent AIDS. A new improved …
Protection 
12/6/12 
Vaginal Microbicide Gel May Offer a Promising Strategy for Prevention And Protection Against HIV Transmission
A new study shows that a microbicide gel is highly effective in block infection by the AIDS virus in a non-human primate model. In the paper published December 6 …
Human 
10/29/13 
HIV - Geneticists Map Human Resistance to AIDS
The key to future HIV treatment could be hidden right in our own genes. Everyone who becomes infected deploys defense strategies, and some even manage to hold the virus …
Virus 
3/21/13 
Findings to Help in Design of Drugs Against Virus Causing Childhood Illnesses
WEST LAFAYETTE, Ind. - New research findings may help scientists design drugs to treat a virus infection that causes potentially fatal brain swelling and paralysis in children. The …
Treatment 
8/23/10 
HIV Virus Hides in the Brain
Studies of the spinal fluid of patients given anti-HIV drugs have resulted in new findings suggesting that the brain can act as a hiding place for the HIV virus. …
Margolis 
3/8/12 
Drug Helps Purge Hidden HIV Virus, Study Shows
A team of researchers at the University of North Carolina at Chapel Hill have successfully flushed latent HIV infection from hiding, with a drug used to treat certain types …
Virus 
3/8/12 
Vaccination Strategy May Hold Key to Ridding HIV Infection from Immune System
Using human immune system cells in the lab, AIDS experts at Johns Hopkins have figured out a way to kill off latent forms of HIV that hide in infected …
Replication 
1/28/14 
Persistent HIV Replication Associated with Lower Drug Concentrations in Lymphatic Tissues
Drugs used to treat HIV penetrate poorly into lymphatic tissues where most HIV replication takes place and there is persistent low-level virus replication in these tissues according to research …
Resistance 
10/3/12 
The Genetics of HIV-1 Resistance
Drug resistance is a major problem when treating infections. This problem is multiplied when the infection, like HIV-1, is chronic. New research published in BioMed Central's open access journal …
More » 
 
© Newsline Group  |  About  |  Privacy Policy  |  Feedback  |  Mobile