Scientists have discovered that the sugar surface of HIV looks like a normal biological complex, according to research published in Nature Chemical Biology this week. The work helps to explain how HIV can sneak past our immune system and may provide new opportunities for anti-HIV drugs.

HIV replicates inside cells but then must travel outside to infect new cells. During this process, part of the cell wall encloses the virus, coating it with a complex mixture of lipids, proteins and sugars. The pathway by which the virus exits cells has not been confirmed, but some evidence suggests that HIV uses the same path as microvesicles, which are natural particles with an unknown function.

Lara Mahal and colleagues show that the sugars on the outside of HIV and microvesicles from the same cell are more closely matched than samples of HIV from different cells. This provides important support for the proposed exit pathway. Additionally, the substantial similarity between the virus which causes AIDS and a natural complex may provide an important clue as to why the immune system cannot effectively identify and destroy this harmful virus.