CAPE TOWN — Scientists have found two powerful new antibodies that disarm HIV, offering fresh clues in the hunt for a vaccine. The antibodies were found in blood samples of volunteers in regions hit hardest by HIV, including SA.
The discovery was one small step towards developing a vaccine against HIV infection as scientists still needed to discover how the antibodies worked and turn these properties into an effective jab, said Linda-Gail Bekker, joint director of the Desmond Tutu HIV/AIDS Centre at the University of Cape Town, who collaborated with US scientists on the research. Despite the history of disappointments, the discovery of areas of vulnerability in the virus was cause for optimism, she said.
Wayne Koff, senior vice-president of research and development at the International AIDS Vaccine Initiative, said: “The findings themselves are an exciting advance towards the goal of an effective AIDS vaccine because now we’ve got a new, potentially better target to focus our efforts (on).
“And having identified one, we’re set up to find more, which should accelerate global efforts in AIDS vaccine development.”
Researchers found two broadly acting neutralising antibodies that appear to stop a wide range of HIV strains from getting a grip on CD4- T cells, which are a key part of the body’s immune system.
“They cling-wrap the virus, and stop it from being able to attach to the host target cell,” said Bekker.
The two broadly acting neutralising antibodies, PG9 and PG16, described in a paper published last week in the US journal Science, are the first to be found in more than a decade. They appear to be more powerful than those previously studied, and as they stick to parts of the HI virus that are more accessible scientists hope they will prove easier to turn into a vaccine.
The antibodies were also the first ones to be isolated among people in the developing world, where the majority of people infected with HIV lived. The breadth of the antibodies’ effect against HIV was important as an effective AIDS vaccine had to work against the ever- increasing number of strains of the virus, said Bekker. HIV mutated fast, and different subtypes dominated in different regions. SA was primarily affected by the C-clade.
The antibodies were discovered using new technology developed by biotechnology companies Theraclone Sciences and Monogram Biosciences that screened blood samples from 1800 HIV-infected volunteers in seven sub-Saharan African countries, Thailand, Australia, the UK and the US.
kahnt@bdfm.co.za