The development of a vaccine against HIV is a global health priority and a tremendous scientific challenge that has been hampered by the extraordinary genetic diversity of HIV and the immune evasive properties of the HIV envelope glycoprotein to which neutralizing antibodies target. Despite the development of antiretroviral therapy that can extend the life of infected individuals, these drugs are not widely available in the underdeveloped world and, thus, a therapeutic vaccine would be of great benefit. (Mariana Varela, The Current State of HIV Vaccine Research)