Featured Research

from universities, journals, and other organizations

High HIV Levels Shut Down Anti-HIV Immune Responses

Date:
November 26, 2001
Source:
NIH/National Institute Of Allergy And Infectious Diseases
Summary:
New research suggests that HIV-specific T cells persist in infected individuals, but high virus levels can diminish the ability of those cells to respond to infection. The report sheds new light on how HIV evades the immune system and establishes long-term infections.

New research suggests that HIV-specific T cells persist in infected individuals, but high virus levels can diminish the ability of those cells to respond to infection. The report sheds new light on how HIV evades the immune system and establishes long-term infections. The research appears in the November 20, 2001 issue of the Proceedings of the National Academy of Sciences.

Related Articles


"HIV infection not only destroys the body's resistance to other pathogens, but it can manipulate the immune system for its own survival," says Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID). "This research provides some important clues to how the virus accomplishes that goal."

In chronic viral infections, CD4+ T cells are required for the immune system to keep virus levels in check. In HIV-infected people, however, few anti-HIV CD4+ T cells proliferate when exposed to viral proteins. Researchers have not known if the absence of a proliferative T-cell response occurs because the virus destroys or merely inactivates HIV-specific CD4+ T cells.

NIAID's Andrew McNeil, M.D., and Mark Connors, M.D., led a study to answer that question. The investigators studied the T cells of three groups of patients: those with progressive HIV infection; a rare subset of individuals with long-term, untreated infection but with viral RNA levels consistently below the level of detection (long-term nonprogressors); and patients on antiretroviral therapy who stopped taking their drugs long enough for virus levels to rebound.

All three groups had equal numbers of HIV-specific CD4+ T cells, indicating the cells were not destroyed by the virus. The HIV-specific CD4+ T cells of people with progressive disease, however, did not respond to the virus by proliferating, suggesting they had somehow been turned off.

To examine the cause and effect relationship between proliferative T-cell responses and immune control over the virus, Drs. McNeil, Connors, and their colleagues turned to the patients who showed anti-HIV T-cell proliferation while taking antiretroviral drugs. The investigators reasoned that if those T cells were keeping HIV levels low, they should continue to do so even if therapy were interrupted. When the researchers stopped the drugs, however, virus levels rebounded in each of the patients. In those individuals, anti-HIV CD4+ T cells were present but lost their ability to proliferate as virus levels increased. Furthermore, the cells maintained their inactive state until antiretroviral drugs brought virus levels back under control.

The results suggest that the loss of HIV-specific T-cell proliferation may not be a cause, but rather is an effect, of high virus levels. Such proliferation, which is present in long-term nonprogressors, therefore does not necessarily predict immune control over the virus.

"This presents a good news/bad news scenario," says Dr. Connors. "The good news is that HIV-specific CD4+ T cells are not completely deleted; the bad news is that measuring the activity or even the frequency of those cells is not necessarily a good predictor of long-term virus control."

The results suggest that long-term interruptions in antiretroviral therapy may not be the best way to stimulate anti-HIV immune responses. The results also provide some clues to how HIV disrupts the immune response to itself and responses to other pathogens.

NIAID is a component of the National Institutes of Health (NIH). NIAID supports basic and applied research to prevent, diagnose, and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, tuberculosis, malaria, autoimmune disorders, asthma and allergies.

Reference: AC McNeil et al. High-level HIV-1 viremia suppresses viral antigen-specific CD4+ T cell proliferation. Proceedings of the National Academy of Sciences 98:13878-83 (2001). 10.1073/pnas.251539598.


Story Source:

The above story is based on materials provided by NIH/National Institute Of Allergy And Infectious Diseases. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Institute Of Allergy And Infectious Diseases. "High HIV Levels Shut Down Anti-HIV Immune Responses." ScienceDaily. ScienceDaily, 26 November 2001. <www.sciencedaily.com/releases/2001/11/011120043617.htm>.
NIH/National Institute Of Allergy And Infectious Diseases. (2001, November 26). High HIV Levels Shut Down Anti-HIV Immune Responses. ScienceDaily. Retrieved October 30, 2014 from www.sciencedaily.com/releases/2001/11/011120043617.htm
NIH/National Institute Of Allergy And Infectious Diseases. "High HIV Levels Shut Down Anti-HIV Immune Responses." ScienceDaily. www.sciencedaily.com/releases/2001/11/011120043617.htm (accessed October 30, 2014).

Share This



More Health & Medicine News

Thursday, October 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Reuters - Innovations Video Online (Oct. 29, 2014) A Swedish amputee who became the first person to ever receive a brain controlled prosthetic arm is able to manipulate and handle delicate objects with an unprecedented level of dexterity. The device is connected directly to his bone, nerves and muscles, giving him the ability to control it with his thoughts. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Google To Use Nanoparticles, Wearables To Detect Disease

Google To Use Nanoparticles, Wearables To Detect Disease

Newsy (Oct. 29, 2014) Google X wants to improve modern medicine with nanoparticles and a wearable device. It's all an attempt to tackle disease detection and prevention. Video provided by Newsy
Powered by NewsLook.com
Can Drinking Milk Lead To Early Death?

Can Drinking Milk Lead To Early Death?

Newsy (Oct. 29, 2014) Researchers in Sweden released a study showing heavy milk drinkers face an increased mortality risk from a variety of causes. Video provided by Newsy
Powered by NewsLook.com
Obama: The US Will Not 'run and Hide' From Ebola

Obama: The US Will Not 'run and Hide' From Ebola

AP (Oct. 29, 2014) Surrounded by health care workers in the White House East Room, President Barack Obama said the U.S. will likely see additional Ebola cases in the weeks ahead. But he said the nation can't seal itself off in the fight against the disease. (Oct. 29) Video provided by AP
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