The HIV virus’ carbohydrate camouflage remains constant across all classes of HIV but differs from the carbohydrate coat found on human cells; targeting this protective layer could form the basis of new AIDS vaccines.
Carbohydrate coating of HIV are unique, and differ from those on human cells
Researchers from the University of Oxford, the Scripps Research Institute in California and the Ragon Institute in Boston isolated the carbohydrate coating from different samples of live HIV-1 virus representing typical viruses found across the world and analysed their chemical structures. They discovered the carbohydrates are unique and found across all classes or clades of HIV.
“We’re cautiously optimistic that this research could lead to a promising new approach for a vaccine against HIV/AIDS,” said Dr Chris Scanlan from the department of biochemistry at Oxford, “We’ve found something that doesn’t change across all classes of HIV – from viruses found in the USA to those in Uganda – and it’s something that can be made and manufactured.”
The researchers hope a vaccine based on synthetic versions of the HIV carbohydrate coat could prime the body’s immune system to recognise the otherwise rapidly changing HIV virus and fight off infection. Existing vaccines do not have the same carbohydrate structures within their formulations as the native HIV and so may not effectively mimic the virus.
The study showed that although the carbohydrate chains making up the camouflage look like those on the outside of the body’s own cells – meaning that they are not normally recognised by the immune system – there are in fact completely different. Scanlan believes this may give us the chance to fight back.
“It is possible to educate the immune system to these differences,” he said, “You can include danger signals in your vaccine formulation to force the immune system to take notice of particular carbohydrate structures.”
The team will now concentrate on making synthetic versions of certain carbohydrates found in the outside of HIV in the lab. These could be combined with adjuvants to give completely new vaccine candidates.