(Undated) -- A discovery on what causes HIV infection could lead to the development of an effective AIDS vaccine. Teams from the Scripps Research Institute and Weill Cornell Medical College have uncovered a protein structure that's key to HIV infection. The researchers say understanding this protein helps explain how HIV invades human cells. Vaccine developers can now pinpoint exactly where HIV antibodies bind to the AIDS virus. More than 34-million people around the world are living with HIV which can lead to AIDS.