Featured Research

from universities, journals, and other organizations

Scientists disarm HIV in step towards vaccine

Date:
September 20, 2011
Source:
Imperial College London
Summary:
Researchers have found a way to prevent HIV from damaging the immune system, in a new lab-based study. The research could have important implications for the development of HIV vaccines.

Researchers have found a way to prevent HIV from damaging the immune system, in a new lab-based study published in the journal Blood. The research, led by scientists at Imperial College London and Johns Hopkins University, could have important implications for the development of HIV vaccines.

HIV/AIDS is the third biggest cause of death in low income countries, killing around 1.8 million people a year worldwide. An estimated 2.6 million people became infected with HIV in 2009.

The research shows that HIV is unable to damage the immune system if cholesterol is removed from the virus's membrane. Usually, when a person becomes infected, the body's innate immune response provides an immediate defence. However, some researchers believe that HIV causes the innate immune system to overreact and that this weakens the immune system's next line of defence, known as the adaptive immune response.

In the new study, the researchers removed cholesterol from the membrane surrounding the virus and found that this stopped HIV from triggering the innate immune response. This led to a stronger adaptive response, orchestrated by immune cells called T cells. These results support the idea that HIV overstimulates the innate response and that this weakens the immune system.

Dr Adriano Boasso, first author of the study, from Imperial College London, said: "HIV is very sneaky. It evades the host's defences by triggering overblown responses that damage the immune system. It's like revving your car in first gear for too long. Eventually the engine blows out.

"This may be one reason why developing a vaccine has proven so difficult. Most vaccines prime the adaptive response to recognise the invader, but it's hard for this to work if the virus triggers other mechanisms that weaken the adaptive response."

HIV takes its membrane from the cell that it infects. This membrane contains cholesterol, which helps to keep it fluid. The fluidity of the membrane enables the virus to interact with particular types of cell. Cholesterol in the cell membrane is not connected to cholesterol in the blood, which is a risk factor for heart disease but is not linked to HIV.

Normally, a subset of immune cells called plasmacytoid dendritic cells (pDCs) recognise HIV quickly and react by producing signalling molecules called interferons. These signals activate various processes which are initially helpful, but which damage the immune system if switched on for too long.

In collaboration with researchers at Johns Hopkins University, the University of Milan and Innsbruck University, Dr Boasso's group at Imperial have discovered that if cholesterol is removed from HIV's envelope, it can no longer activate pDCs. As a consequence, T cells, which orchestrate the adaptive response, can fight the virus more effectively.

The researchers removed cholesterol using varying concentrations of beta-cyclodextrin (bCD), a derivative of starch that binds cholesterol. Using high levels of bCD they produced a virus with a large hole in its envelope. This permeabilised virus was not infectious and could not activate pDCs, but was still recognised by T cells. Dr Boasso and his colleagues are now looking to investigate whether this inactivated virus could be developed into a vaccine.

"It's like an army that has lost its weapons but still has flags, so another army can recognise it and attack it," he said.

The research was funded by the Wellcome Trust and the National Institutes of Health.


Story Source:

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


Journal Reference:

  1. Adriano Boasso, Caroline M. Royle, Spyridon Doumazos, Veronica N. Aquino, Mara Biasin, Luca Piacentini, Barbara Tavano, Dietmar Fuchs, Francesco Mazzotta, Sergio Lo Caputo, Gene M Shearer, Mario Clerici, David R. Graham. Over-activation of plasmacytoid dendritic cell inhibits anti-viral T-cell responses: a model for HIV immunopathogenesis. Blood, 2011 DOI: 10.1182/blood-2011-03-344218

Cite This Page:

Imperial College London. "Scientists disarm HIV in step towards vaccine." ScienceDaily. ScienceDaily, 20 September 2011. <www.sciencedaily.com/releases/2011/09/110919171336.htm>.
Imperial College London. (2011, September 20). Scientists disarm HIV in step towards vaccine. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2011/09/110919171336.htm
Imperial College London. "Scientists disarm HIV in step towards vaccine." ScienceDaily. www.sciencedaily.com/releases/2011/09/110919171336.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
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:
from the past week

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