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J Biol Chem. 2014 Oct 24;289(43):29912-26. doi: 10.1074/jbc.M114.569566. Epub 2014 Aug 26.

A fusion intermediate gp41 immunogen elicits neutralizing antibodies to HIV-1.

Author information

1
From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom.
2
Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France.
3
Institute of Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
4
Novartis Vaccines and Diagnostics Inc., Cambridge, Massachusetts 02139.
5
National Institute for Communicable Diseases, Centre for HIV and Sexually Transmitted Infections, 1 Modderfontein Road, Sandringham 2131, South Africa.
6
Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, and.
7
Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115.
8
From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom, jlh66@cam.ac.uk.
9
Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France, weissenhorn@embl.fr.

Abstract

The membrane-proximal external region (MPER) of the human immunodeficiency virus, type 1 (HIV-1) envelope glycoprotein subunit gp41 is targeted by potent broadly neutralizing antibodies 2F5, 4E10, and 10E8. These antibodies recognize linear epitopes and have been suggested to target the fusion intermediate conformation of gp41 that bridges viral and cellular membranes. Anti-MPER antibodies exert different degrees of membrane interaction, which is considered to be the limiting factor for the generation of such antibodies by immunization. Here we characterize a fusion intermediate conformation of gp41 (gp41(int)-Cys) and show that it folds into an elongated ∼ 12-nm-long extended structure based on small angle x-ray scattering data. Gp41(int)-Cys was covalently linked to liposomes via its C-terminal cysteine and used as immunogen. The gp41(int)-Cys proteoliposomes were administered alone or in prime-boost regimen with trimeric envelope gp140(CA018) in guinea pigs and elicited high anti-gp41 IgG titers. The sera interacted with a peptide spanning the MPER region, demonstrated competition with broadly neutralizing antibodies 2F5 and 4E10, and exerted modest lipid binding, indicating the presence of MPER-specific antibodies. Although the neutralization potency generated solely by gp140(CA018) was higher than that induced by gp41(int)-Cys, the majority of animals immunized with gp41(int)-Cys proteoliposomes induced modest breadth and potency in neutralizing tier 1 pseudoviruses and replication-competent simian/human immunodeficiency viruses in the TZM-bl assay as well as responses against tier 2 HIV-1 in the A3R5 neutralization assay. Our data thus demonstrate that liposomal gp41 MPER formulation can induce neutralization activity, and the strategy serves to improve breadth and potency of such antibodies by improved vaccination protocols.

KEYWORDS:

AIDS; HIV-1; HIV-1 gp41; Membrane Fusion; Protein Conformation; Vaccine Development; X-ray Scattering

PMID:
25160627
PMCID:
PMC4208001
DOI:
10.1074/jbc.M114.569566
[Indexed for MEDLINE]
Free PMC Article

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