Featured Research

from universities, journals, and other organizations

Scientists find invisibility cloak that shields HIV-1 from immune system

Date:
November 21, 2013
Source:
Cell Press
Summary:
Of the two major types of HIV, only one, HIV-1, typically causes AIDS in infected people who don't receive treatment. A study reveals how HIV-1 escapes detection by essentially becoming invisible to a patient's immune system, whereas HIV-2 triggers protective immune responses in patients. This understanding of how HIV-1's "invisibility cloak" works could lead to the development of effective vaccines against HIV-1.

The image depicts an HIV-2 virus (left) getting in contact with a dendritic cell (right). When the virus enters the dendritic cell, the capsid shell (cone) containing a viral RNA (line) can get efficiently reverse-transcribed into DNA through activity of the Vpx protein (orange) that degrades SAMHD1 (not shown). The resulting cDNA (double line) has two different fates, which are determined by the sequence of the capsid and its interaction with Cyclophilin A proteins (red drops). In HIV-2 and capsid-mutated viruses described in the paper, the cDNA gets sensed by the cytosolic sensor cGAS (radar) leading to induction of antiviral and immune response gene expression. In HIV-1, the capsid allows the virus to escape sensing of its viral cDNA, leading to productive infection of the cell (integrated cDNA in the nucleus).
Credit: Nicolas Manel

Of the two major types of HIV, only one, HIV-1, typically causes AIDS in infected people who don't receive treatment. A study published by Cell Press November 21st in the journal Immunity reveals how HIV-1 escapes detection by essentially becoming invisible to a patient's immune system, whereas HIV-2 triggers protective immune responses in patients. This understanding of how HIV-1's "invisibility cloak" works could lead to the development of effective vaccines against HIV-1.

Related Articles


"Our study shows for the first time exactly how immune cells sense the virus and how the virus uses one of its proteins to tune its stealthiness and infectivity," says senior study author Nicolas Manel of the Institut Curie. "We also show how to modify the virus so that it is properly recognized and leads to a beneficial immune response."

Individuals who are infected with both HIV-1 and HIV-2 do better than those infected with HIV-1 alone, suggesting that the immune response against HIV-2 protects against the effects of HIV-1 infection. While searching for an explanation in previous studies, Manel and his collaborators found that HIV-2, but not HIV-1, naturally infects and activates dendritic cells, which play a major role in triggering protective immune responses. But until now, it was not known how HIV is detected in dendritic cells.

In the new study, Manel and his team focused on the capsid—the protein shell of a virus that encloses its genetic material. By mutating HIV-1 and HIV-2 capsids, they discovered that these viral proteins control the ability of dendritic cells to sense the viruses and activate immune responses.

The researchers found that the HIV-1 capsid allows the virus to escape detection by dendritic cells under normal conditions. But when they mutated the HIV-1 and HIV-2 capsids, the dendritic cells produced immune responses without getting infected by the viruses. These cells relied on a protein called cyclic GMP-AMP synthase (cGAS) to sense the viral DNA in the cytosol before the foreign DNA became integrated into the host genome.

These findings open new avenues for the development of effective treatments against HIV-1. "By modifying the capsid of a virus, we could engineer a virus that is both better recognized by the immune system and that has also lost its ability to infect cells," Manel says. "Beyond capsid-mutated viruses, our results suggest that activating the cGAS pathway in dendritic cells could induce immunity against HIV-1."


Story Source:

The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.


Journal Reference:

  1. Lahaye et al. The capsids of HIV-1 and HIV-2 determine immune detection of the viral cDNA by the innate sensor cGAS in dendritic cells. Immunity, November 2013

Cite This Page:

Cell Press. "Scientists find invisibility cloak that shields HIV-1 from immune system." ScienceDaily. ScienceDaily, 21 November 2013. <www.sciencedaily.com/releases/2013/11/131121125903.htm>.
Cell Press. (2013, November 21). Scientists find invisibility cloak that shields HIV-1 from immune system. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2013/11/131121125903.htm
Cell Press. "Scientists find invisibility cloak that shields HIV-1 from immune system." ScienceDaily. www.sciencedaily.com/releases/2013/11/131121125903.htm (accessed December 21, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Sunday, December 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Best Tips to Curb Holiday Carbs

The Best Tips to Curb Holiday Carbs

Buzz60 (Dec. 19, 2014) It's hard to resist those delicious but fattening carbs we all crave during the winter months, but there are some ways to stay satisfied without consuming the extra calories. Vanessa Freeman (@VanessaFreeTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Sierra Leone Bikers Spread the Message to Fight Ebola

Sierra Leone Bikers Spread the Message to Fight Ebola

AFP (Dec. 19, 2014) More than 100 motorcyclists hit the road to spread awareness messages about Ebola. Nearly 7,000 people have now died from the virus, almost all of them in west Africa, according to the World Health Organization. Video provided by AFP
Powered by NewsLook.com
Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
The Best Protein-Filled Foods to Energize You for the New Year

The Best Protein-Filled Foods to Energize You for the New Year

Buzz60 (Dec. 19, 2014) The new year is coming and nothing will energize you more for 2015 than protein-filled foods. Fitness and nutrition expert John Basedow (@JohnBasedow) gives his favorite high protein foods that will help you build muscle, lose fat and have endless energy. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins