Broadly neutralizing antibodies have been discovered in ~5% of HIV+ individuals. Some of those antibodies (HIV bnAbs) are capable of neutralizing over 70% of all known HIV isolates. Finally, providing a single intravenous injection of a single HIV bnAb into macaques completely protects the animals from a lethal mucosal (vaginal) SHIV challenge. These three facts provide proof-of-principle that a neutralizing antibody HIV vaccine strategy could be highly protective in humans. However, while those proof-of-principle experiments have shown the validity of the concept, major scientific and technical obstacles make most observers skeptical that a neutralizing antibody HIV vaccine will be possible. The Crotty laboratory, as part of the CHAVI-ID consortium, is intensively pursuing the idea that a neutralizing antibody HIV vaccine is possible (Burton et al., Cell Host and Microbe 2012), and it will depend on optimized Tfh cell and germinal center responses to driven the necessary affinity maturation to obtain HIV broadly neutralizing antibodies via immunization (Locci et al., Immunity 2013; Crotty Immunity 2014).