2F5 is a broadly neutralizing human monoclonal antibody that has been shown to bind to and neutralize HIV-1 in vitro, making it a potential candidate for use in vaccine synthesis. 2F5 recognizes an epitope in the membrane-proximal external region of HIV-1 gp41. 2F5 then binds to this epitope and its constant region interacts with the viral lipid membrane, which neutralizes the virus. Wikipedia