Structural and genetic basis of HIV-1 envelope V2 apex recognition by rhesus broadly neutralizing antibodies.

Broadly neutralizing antibodies targeting the V2 apex of HIV-1 envelope are desired as vaccine design templates, but few have been described. Here, we report 11 lineages of V2 apex-neutralizing antibodies from simian-human immunodeficiency virus (SHIV)-infected rhesus macaques and determine cryo-EM structures for 9. A single V2 apex-neutralizing lineage accounted for cross-clade breadth in most macaques, and somatic hypermutation relative to breadth was generally low, exemplified by antibody V033-a.01 with <5% nucleotide mutation and 37% breadth (208-strain panel). Envelope complex structures revealed eight different antibody classes (one multi-donor) and the complete repertoire of all five possible recognition topologies, recapitulating canonical human modes of apex insertion and C-strand hydrogen bonding. Despite this diversity in recognition, all rhesus-V2 apex antibodies were derived from reading frame two of the DH3-15*01 gene. Collectively, these results define-in rhesus-the structural and genetic basis of HIV-1 V2 apex recognition and demonstrate unprecedented structural plasticity of a highly selected immunogenetic element.