Study discovers unique feature of HIV that helps to create antibodies

October 22, 2012, Wits University

Wits researchers have played a pivotal role in an AIDS study published today in the journal, Nature Medicine, which describes how a unique change in the outer covering of the virus found in two HIV infected South African women enabled them to make potent antibodies which are able to kill up to 88% of HIV types from around the world.

This ground-breaking discovery provides an important new approach that could be useful in making an .

The study, performed by members of the Centre for the Aids Programme of Research in South Africa (CAPRISA) consortium, involves scientists from Wits University, the National Institute for Communicable Diseases (NICD) in Johannesburg, the University of KwaZulu-Natal and the University of Cape Town, who has been studying, over the last five years, how certain HIV-infected people develop very powerful .

These antibodies are referred to as broadly neutralising antibodies because they kill a wide range of HIV types from different parts of the world. This CAPRISA team initially discovered that two KwaZulu-Natal women, one of whom participated in the CAPRISA 004 gel study, could make these rare antibodies.

Through long-term follow-up laboratory studies on these two women, the team led by Wits researchers and Centre for HIV and STI at the National Institute for Communicable Diseases of the National Health Laboratory Service based scientists Dr Penny Moore and Professor Lynn Morris, discovered that a sugar (known as a glycan) on the surface of the at a specific position (referred to as position 332) forms a site of vulnerability in the virus and enables the body to mount a broadly neutralizing antibody response.

"Understanding this elaborate game of 'cat and mouse' between HIV and the immune response of the infected person has provided valuable insights into how broadly neutralizing antibodies arise," says Moore.

Morris, Head of AIDS Research at the NICD explained: "We were surprised to find that the virus that caused infection in many cases did not have this antibody target on its outer covering. But over time, the virus was pressured by body's immune reaction to cover itself with the sugar that formed a point of vulnerability, and so allowed the development of antibodies that hit that weak spot".

"Broadly neutralising antibodies are considered to be the key to making an AIDS vaccine. This discovery provides new clues on how vaccines could be designed to elicit broadly neutralising antibodies. The world needs an effective AIDS vaccine to overcome the global scourge of AIDS," said Professor Salim Abdool Karim, Director of CAPRISA and President of the Medical Research Council, in his comments on the significance of the finding.

While their existence has been known for a while, highly potent forms of broadly neutralizing antibodies against HIV were only identified about 3 years ago. Until now, it was not known how the human body is able to make broadly neutralizing antibodies.

This study discovered one mechanism by which these antibodies may be made. To make this discovery, the research team studied the target of some of these antibodies, a sugar that coats the of HIV, forming a site of vulnerability. By tracing back the evolution of the virus that elicited these antibodies, this team showed that this particular weak point was absent from the virus that first infected these women.

However, under constant pressure from other less powerful antibodies that develop in all infected people, their HIV was forced to expose this vulnerability over time. This allowed the broadly neutralizing to develop.

Analysis of a large number of other viruses from throughout the world, performed in collaboration with scientists from the University of North Carolina and Harvard University, suggest that the vulnerability at position 332 may be present at the time of infection in about two thirds of subtype C viruses (the subtype most common in Africa). Hence, if a vaccine is developed to target this glycan only, it may not be able to uniformly neutralize all subtype C viruses; as a result vaccines may need to attack multiple targets on the virus.

Explore further: Researchers discuss challenges to developing broadly protective HIV vaccines

Related Stories

Researchers discuss challenges to developing broadly protective HIV vaccines

September 7, 2011
The human body can produce powerful antibodies that shield cells in the laboratory against infection by an array of HIV strains. In people, however, recent research shows that these broadly neutralizing antibodies are not ...

Researchers determine how antibody recognizes key sugars on HIV surface

November 23, 2011
HIV is coated in sugars that usually hide the virus from the immune system. Newly published research reveals how one broadly neutralizing HIV antibody actually uses part of the sugary cloak to help bind to the virus. The ...

Neutralizing HIV

July 18, 2011
Each time a virus invades a healthy individual, antibodies created by the body fight to fend off the intruders. For some viruses, like HIV, the antibodies are very specific and are generated too slowly to combat the rapidly ...

Recommended for you

War in Ukraine has escalated HIV spread in the country: study

January 15, 2018
Conflict in Ukraine has increased the risk of HIV outbreaks throughout the country as displaced HIV-infected people move from war-affected regions to areas with higher risk of transmission, according to analysis by scientists.

Researchers offer new model for uncovering true HIV mortality rates in Zambia

January 12, 2018
A new study that seeks to better ascertain HIV mortality rates in Zambia could provide a model for improved national and regional surveillance approaches, and ultimately, more effective HIV treatment strategies.

New drug capsule may allow weekly HIV treatment

January 9, 2018
Researchers at MIT and Brigham and Women's Hospital have developed a capsule that can deliver a week's worth of HIV drugs in a single dose. This advance could make it much easier for patients to adhere to the strict schedule ...

New long-acting, less-toxic HIV drug suppresses virus in humanized mice

January 8, 2018
A team of Yale researchers tested a new chemical compound that suppresses HIV, protects immune cells, and remains effective for weeks with a single dose. In animal experiments, the compound proved to be a promising new candidate ...

Usage remains low for pill that can prevent HIV infection

January 8, 2018
From gritty neighborhoods in New York and Los Angeles to clinics in Kenya and Brazil, health workers are trying to popularize a pill that has proven highly effective in preventing HIV but which—in their view—remains woefully ...

Researchers find clues to AIDS resistance in sooty mangabey genome

January 3, 2018
Peaceful co-existence, rather than war: that's how sooty mangabeys, a monkey species found in West Africa, handle infection by SIV, a relative of HIV, and avoid developing AIDS-like disease.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Minnaloushe
1 / 5 (2) Oct 22, 2012
I lose count of how many times this has been "discovered". Piffle.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.