Structure and Recognition of a Novel HIV-1 gp120-gp41 Interface Antibody that Caused MPER Exposure through Viral Escape
| Autor: | Dennis R. Burton, Julie. Rouelle, Daniel J. Sheward, M. Gordon Joyce, Andrew B. Ward, Peter D. Kwong, Constantinos Kurt Wibmer, Carolyn Williamson, Lynn Morris, Nonkululeko. Ndabambi, Jason Gorman, Ashley. Smira, James E. Robinson, Penny L. Moore, Jinal N. Bhiman, Debra Holton Elliott, Aliaksandr Druz, John R. Mascola, Gabriel Ozorowski, Mark Connors, Salim S. Abdool Karim, Mangai Asokan |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
RNA viruses
0301 basic medicine Glycosylation HIV Antigens Physiology viruses Glycobiology HIV Infections Complementarity determining region HIV Antibodies HIV Envelope Protein gp120 Crystallography X-Ray Pathology and Laboratory Medicine Biochemistry Neutralization Epitope Epitopes Immunodeficiency Viruses Immune Physiology Medicine and Health Sciences Enzyme-Linked Immunoassays Post-Translational Modification lcsh:QH301-705.5 Immune System Proteins Crystallography Physics Microbial Mutation Antibodies Monoclonal Hematology Condensed Matter Physics HIV Envelope Protein gp41 Recombinant Proteins Body Fluids 3. Good health Blood Medical Microbiology Viral Pathogens CD4 Antigens Viruses Physical Sciences Crystal Structure Pathogens Anatomy Antibody Research Article lcsh:Immunologic diseases. Allergy medicine.drug_class Immunology Biology Research and Analysis Methods Monoclonal antibody Microbiology Antibodies Blood Plasma 03 medical and health sciences Neutralization Tests Cell Line Tumor Virology Retroviruses Genetics medicine Humans Solid State Physics Immunoassays Microbial Pathogens Molecular Biology Immune Evasion Linear epitope Lentivirus Organisms Biology and Life Sciences Proteins HIV Viral membrane Antibodies Neutralizing Complementarity Determining Regions Molecular biology Monoclonal Antibodies 030104 developmental biology lcsh:Biology (General) HIV-1 Immunologic Techniques biology.protein Parasitology Paratope Binding Sites Antibody lcsh:RC581-607 HeLa Cells |
| Zdroj: | PLoS Pathogens, Vol 13, Iss 1, p e1006074 (2017) PLoS Pathogens |
| ISSN: | 1553-7374 1553-7366 |
| Popis: | A comprehensive understanding of the regions on HIV-1 envelope trimers targeted by broadly neutralizing antibodies may contribute to rational design of an HIV-1 vaccine. We previously identified a participant in the CAPRISA cohort, CAP248, who developed trimer-specific antibodies capable of neutralizing 60% of heterologous viruses at three years post-infection. Here, we report the isolation by B cell culture of monoclonal antibody CAP248-2B, which targets a novel membrane proximal epitope including elements of gp120 and gp41. Despite low maximum inhibition plateaus, often below 50% inhibitory concentrations, the breadth of CAP248-2B significantly correlated with donor plasma. Site-directed mutagenesis, X-ray crystallography, and negative-stain electron microscopy 3D reconstructions revealed how CAP248-2B recognizes a cleavage-dependent epitope that includes the gp120 C terminus. While this epitope is distinct, it overlapped in parts of gp41 with the epitopes of broadly neutralizing antibodies PGT151, VRC34, 35O22, 3BC315, and 10E8. CAP248-2B has a conformationally variable paratope with an unusually long 19 amino acid light chain third complementarity determining region. Two phenylalanines at the loop apex were predicted by docking and mutagenesis data to interact with the viral membrane. Neutralization by CAP248-2B is not dependent on any single glycan proximal to its epitope, and low neutralization plateaus could not be completely explained by N- or O-linked glycosylation pathway inhibitors, furin co-transfection, or pre-incubation with soluble CD4. Viral escape from CAP248-2B involved a cluster of rare mutations in the gp120-gp41 cleavage sites. Simultaneous introduction of these mutations into heterologous viruses abrogated neutralization by CAP248-2B, but enhanced neutralization sensitivity to 35O22, 4E10, and 10E8 by 10-100-fold. Altogether, this study expands the region of the HIV-1 gp120-gp41 quaternary interface that is a target for broadly neutralizing antibodies and identifies a set of mutations in the gp120 C terminus that exposes the membrane-proximal external region of gp41, with potential utility in HIV vaccine design. Author Summary Our understanding of which regions of the HIV-1 envelope are targets for broadly neutralizing antibodies (likely required for an HIV-1 vaccine) has expanded greatly in recent years, offering insights for vaccine design. For instance, much of solvent-exposed gp41 is now known to be targeted by antibodies at the gp120-gp41 interface. In this study, we isolated the neutralizing monoclonal antibody CAP248-2B, and used structural biology to characterize its epitope which spanned both the gp120-gp41 and gp41-gp41 interfaces in a manner distinct from other antibodies. CAP248-2B extends the interface target to include the gp120 C terminus, effectively encircling the base of native pre-fusion trimers. While CAP248-2B recapitulated the donor’s plasma breadth, it had poor potency against some isolates as a consequence of low neutralization plateaus. Unlike many broadly neutralizing antibodies, these plateaus did not appear to be a consequence of glycan heterogeneity, suggesting additional mechanisms that contribute towards incomplete neutralization. Finally, we characterized viral escape pathways from CAP248-2B, and identified a cluster of unusual mutations in the gp160 cleavage sites that made HIV-1 viruses more sensitive to antibodies targeting highly conserved membrane-proximal epitopes. These mutations might improve the immunogenicity of gp41, and thereby inform HIV-1 immunogen design. |
| Databáze: | OpenAIRE |
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