Scientists ‘disarm’ HIV in step towards vaccine
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.”