HIV vaccine closer after antibodies breakthrough

Tue, Oct 23, 2012, 01:00

MEDICAL RESEARCH by a team of South African scientists has revealed how two HIV-positive women’s bodies were able to produce antibodies capable of killing nine of the 10 known strains of the virus.

The development, which was first made public on Sunday, was hailed yesterday as a significant breakthrough in the fight against the deadly disease, as researchers believe it has taken them closer to developing a vaccine that prevents HIV infection.

The World Health Organisation’s latest statistics show that 34.2 million people are infected with the HIV virus and another 25 million people have died from it, or associated diseases, over the past three decades.

Creating a vaccine that can kill the virus has proved elusive because the number of strains of the disease keeps increasing.

Scientists have known for some time that one in five people infected by HIV have the capability of producing antibodies that can fight it after a number of years, but until now they were unable to say how the process occurred.

After studying two women whose bodies were capable of producing the antibodies they have finally solved the mystery, according to Penny Moore, lead author of a paper describing the discovery and a senior scientist at the National Institute for Communicable Diseases.

“We’re hoping we can use this information to develop a vaccine that prompts the body’s immune system to make broadly neutralising antibodies,” she said in the paper published in the journal Nature Medicine.

Also involved in the study were the Centre for Aids Programme of Research in South Africa, the universities of Cape Town and KwaZulu-Natal, and the US universities of North Carolina and Harvard.

The first of the two women that were the subjects of the study joined the research team in 2005 and the other in 2007.

Following extensive research the scientists discovered that when the HIV virus evolves to evade its host’s immune system, by adding a sugar molecule to its surface, the host’s antibodies adapted to recognise the sugar in such a way that they can kill nine of 10 known strains of HIV.

However, these broadly acting antibodies cannot cure HIV, but rather they stop the virus from infecting healthy cells, said Dr Moore. The discovery has been widely welcomed by a scientific community that must replicate the South Africans results before efforts to create a new vaccine based on the findings can be launched.

“Once we can see how [broadly neutralising antibodies] arise naturally, during infection, it becomes much more realistic to think that we can design vaccine strategies to induce similar neutralising antibodies,” John Mascola of the US National Institutes of Allergy and Infectious Diseases told reporters.