A discovery about the way HIV attacks the immune system could pave the way for the development of new treatments. Skip related content Researchers have identified a new method in which the human immunodeficiency virus, which causes Aids, is able to prevent tetherin - a protein found naturally in human cells - from doing its job of blocking the invaders. This highly-skilled study has been carried out by a team based in Montreal in Canada. The hope now is that this information will help scientists to target certain aspects of the virus and therefore develop new anti-HIV drugs. At the moment, there is no way of knowing how much of a difference this discovery will make to HIV therapy and any such developments could take decades. Almost 33 million people around the world are thought to be living with HIV and AIDS.