The HIV envelope spike protein complex is the only exposed target on the viral membrane for neutralizing antibodies. It is generally thought that presentation of envelope proteins in a highly multivalent form from the surface of a particle may contribute to the development of strong and durable neutralizing antibody responses in immunization. In a multi-lab, multi-disciplinary collaboration we have engineered lipid-based nanoparticles that display clinically-relevant envelope proteins (termed SOSIP). The oriented coupling of the proteins to the surface of the nanoparticles not only mimics the way the proteins are naturally displayed on the HIV virus, but also biases antibodies to be targeted to certain desirable sites on the proteins. This is a highly translatable nanoparticle platform that has the potential to be the basis for an eventual prophylactic HIV vaccine.