Abstract
VRC01 broadly neutralizing antibodies (bnAbs) target the CD4-binding site (CD4 BS ) of the human immunodeficiency virus-1 (HIV-1) envelope glycoprotein (Env). Unlike mature antibodies, corresponding VRC01 germline precursors poorly bind to Env. Immunogen design has mostly relied on glycan removal from trimeric Env constructs and has had limited success in eliciting mature VRC01 bnAbs. To better understand elicitation of such bnAbs, we characterized the inferred germline precursor of VRC01 in complex with a modified trimeric 426c Env by cryo-electron microscopy and a 426c gp120 core by X-ray crystallography, biolayer interferometry, immunoprecipitation, and glycoproteomics. Our results show VRC01 germline antibodies interacted with a wild-type 426c core lacking variable loops 1–3 in the presence and absence of a glycan at position Asn276, with the latter form binding with higher affinity than the former. Interactions in the presence of an Asn276 oligosaccharide could be enhanced upon carbohydrate shortening, which should be considered for immunogen design.
| Original language | English |
|---|---|
| Article number | e37688 |
| Journal | eLife |
| Volume | 7 |
| DOIs | |
| Publication status | Published - 7 Nov 2018 |
| Externally published | Yes |
Funding
Research reported in this publication was supported by grants from the National Institute of General Medical Sciences under Award Number R01GM120553 (DV) and T32GM008268 (AJB), the National Institute of Allergy and Infectious Diseases under award numbers R01AI081625 (LS), R01AI104384 (LS), P01AI094419 (LS) and U19AI109632 (LS), a Pew Biomedical Scholars Award (DV), an Investigators in the Pathogenesis of Infectious Disease Award from the Burroughs Wellcome Fund (DV) the Netherlands Organization for Scientific Research (NWO, Rubicon 019.2015.2.310.006; JS) and the European Molecular Biology Organisation (EMBO, ALTF 933–2015; JS).The authors acknowledge the use of instruments at the Electron Imaging Center for NanoMachines supported by NIH (1U24GM116792, 1S10RR23057 and 1S10OD018111), NSF (DBI-1338135) and CNSI at UCLA. This work was also partly supported by the University of Washington Arnold and Mabel Beckman cryoEM center and the Proteomics Resource (UWPR95794). We also thank Priska von Haller for her assistance in using the mass spectrometry instruments. Support for this work was provided in part by the Intramural research program of the Vaccine Research Center, NIAID, NIH. We thank the J B Pendle-ton Charitable Trust for its generous support of Formulatrix robotic instruments. X-ray diffraction data was collected at the Berkeley Center for Structural Biology beamline 5.0.2, which is supported in part by the National Institute of General Medical Sciences. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the United States Department of Energy under contract number DE-AC02-05CH11231. We thank members of the Structural Biology Section and Structural Bioinformatics Core, Vaccine Research Center, for discussions or comments on the manuscript and in particular Hui Geng for providing Env trimer used in crystallization trials and Reda Rawi for providing glycan statistics using the HIV database.
