A Broadly Neutralizing Antibody Targets the Dynamic HIV Envelope Trimer Apex via a Long, Rigidified, and Anionic beta-Hairpin Structure

作者：Lee Jeong Hyun; Andrabi Raiees; Su Ching Yao; Yasmeen Anila; Julien Jean Philippe; Kong Leopold; Wu Nicholas C; McBride Ryan; Sok Devin; Pauthner Matthias; Cottrell Christopher A; Nieusma Travis; Blattner Claudia; Paulson James C; Klasse Per Johan; Wilson Ian A; Burton Dennis R; Ward Andrew B

来源：Immunity, 2017, 46(4): 690-702.

DOI：10.1016/j.immuni.2017.03.017

Broadly neutralizing antibodies (bnAbs) to HIV delineate vaccine targets and are prophylactic and therapeutic agents. Some of the most potent bnAbs target a quaternary epitope at the apex of the surface HIV envelope (Env) trimer. Using cryo-electron microscopy, we solved the atomic structure of an apex bnAb, PGT145, in complex with Env. We showed that the long anionic HCDR3 of PGT145 penetrated between glycans at the trimer 3-fold axis, to contact peptide residues from all three Env protomers, and thus explains its highly trimer-specific nature. Somatic hypermutation in the other CDRs of PGT145 were crucially involved in stabilizing the structure of the HCDR3, similar to bovine antibodies, to aid in recognition of a cluster of conserved basic residues hypothesized to facilitate trimer disassembly during viral entry. Overall, the findings exemplify the creative solutions that the human immune system can evolve to recognize a conserved motif buried under a canopy of glycans.

• 出版日期2017-4-18