A designed chimeric virus induced broadly neutralizing antibodies against the macaque equivalent of HIV. The strategy works in two steps: first it uses an envelope protein with a mutation that reduces the glycan shield that makes it invisible to the immune system, and then it exposes the part of the protein most likely to generate these antibodies capable of blocking many variants of the virus. The macaques developed potent and diverse antibodies with this approach, which pave the way for the development of an HIV-1 vaccine.