scholarly journals Characterization of Stable, Soluble Trimers Containing Complete Ectodomains of Human Immunodeficiency Virus Type 1 Envelope Glycoproteins

2000 ◽  
Vol 74 (12) ◽  
pp. 5716-5725 ◽  
Author(s):  
Xinzhen Yang ◽  
Michael Farzan ◽  
Richard Wyatt ◽  
Joseph Sodroski
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cleavage Site ◽  
Neutralizing Antibodies ◽  
Coiled Coil ◽  
Envelope Glycoproteins ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins function as a membrane-anchored trimer of three gp120 exterior glycoproteins and three gp41 transmembrane glycoproteins. Previously, we reported three approaches to stabilize soluble trimers containing parts of the gp41 ectodomains: addition of GCN4 trimeric helices, disruption of the cleavage site between gp120 and gp41, and introduction of cysteines in the gp41 coiled coil to form intersubunit disulfide bonds. Here, we applied similar approaches to stabilize soluble gp140 trimers including the complete gp120 and gp41 ectodomains. A combination of fusion with the GCN4 trimeric sequences and disruption of the gp120-gp41 cleavage site resulted in relatively homogeneous gp140 trimers with exceptional stability. The gp120 epitopes recognized by neutralizing antibodies are intact and exposed on these gp140 trimers. By contrast, the nonneutralizing antibody epitopes on the gp120 subunits of the soluble trimers are relatively occluded compared with those on monomeric gp120 preparations. This antigenic similarity to the functional HIV-1 envelope glycoproteins and the presence of the complete gp41 ectodomain should make the soluble gp140 trimers useful tools for structural and immunologic studies.

scholarly journals Highly Stable Trimers Formed by Human Immunodeficiency Virus Type 1 Envelope Glycoproteins Fused with the Trimeric Motif of T4 Bacteriophage Fibritin

2002 ◽  
Vol 76 (9) ◽  
pp. 4634-4642 ◽  
Author(s):  
Xinzhen Yang ◽  
Juliette Lee ◽  
Erin M. Mahony ◽  
Peter D. Kwong ◽  
Richard Wyatt ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Envelope Glycoproteins ◽  
Immunodeficiency Virus ◽  
T4 Bacteriophage ◽  
Hiv 1

ABSTRACT The envelope glycoproteins of human immunodeficiency virus type 1 (HIV-1) function as a trimer composed of three gp120 exterior glycoproteins and three gp41 transmembrane proteins. Soluble gp140 glycoproteins composed of the uncleaved ectodomains of gp120 and gp41 form unstable, heterogeneous oligomers, but soluble gp140 trimers can be stabilized by fusion with a C-terminal, trimeric GCN4 motif (X. Yang et al., J. Virol. 74:5716-5725, 2000). To understand the influence of the C-terminal trimerization domain on the properties of soluble HIV-1 envelope glycoprotein trimers, uncleaved, soluble gp140 glycoproteins were stabilized by fusion with another trimeric motif derived from T4 bacteriophage fibritin. The fibritin construct was more stable to heat and reducing conditions than the GCN4 construct. Both GCN4- and fibritin-stabilized soluble gp140 glycoproteins exhibited patterns of neutralizing and nonneutralizing antibody binding expected for the functional envelope glycoprotein spike. Of note, two potently neutralizing antibodies, immunoglobulin G1b12 and 2G12, exhibited the greatest recognition of the stabilized, soluble trimers, relative to recognition of the gp120 monomer. The observed similarities between the GCN4 and fibritin constructs indicate that the HIV-1 envelope glycoprotein ectodomains dictate many of the antigenic and structural features of these fusion proteins. The melting temperatures and ligand recognition properties of the GCN4- and fibritin-stabilized soluble gp140 glycoproteins suggest that these molecules assume conformations distinct from that of the fusion-active, six-helix bundle.

scholarly journals Enhancement of human immunodeficiency virus type 1 infection by antisera to peptides from the envelope glycoproteins gp120/gp41.

1991 ◽  
Vol 174 (6) ◽  
pp. 1557-1563 ◽  
Author(s):  
S B Jiang ◽  
K Lin ◽  
A R Neurath
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Rational Design ◽  
Envelope Glycoproteins ◽  
V3 Loop ◽  
Immunodeficiency Virus ◽  
Hiv 1

Human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins (gp120 and gp41) elicit virus-neutralizing antibodies (VNAB) and also antibodies enhancing HIV-1 infection (EAB). Several epitopes eliciting VNAB have been defined, the principal virus-neutralizing determinant being assigned to the V3 loop of gp120. To provide a background for a rational design of anti-HIV vaccines, it also appears important to define domains eliciting EAB. This was accomplished by screening antisera against synthetic peptides covering almost the entire sequence of gp120/gp41 for their enhancing effects on HIV-1 infection of MT-2 cells, a continuous T cell line. Many (16/30) of the antisera significantly enhanced HIV-1 in the presence of human complement. Antibodies to complement receptor type 2 (CR2) abrogated the antibody-mediated enhancement of HIV-1 infection. Antisera to V3 hypervariable loops of 21 distinct HIV-1 isolates were also tested for their enhancing effects on HIV-1IIIB infection. 11 of these sera contained VNAB and 10 enhanced HIV-1IIIB infection. All antisera with virus-enhancing activity contained antibodies crossreactive with the V3 loop of HIV-1IIIB, and the virus-enhancing activity increased with increasing serological crossreactivity. These results suggest that immunization with antigens encompassing V3 loops may elicit EAB rather than protective antibodies if epitopes on the immunogen and the predominant HIV-1 isolate infecting a population are insufficiently matched, i.e., crossreactive serologically but not at the level of virus neutralization.

scholarly journals Neutralizing Antibody Responses in Acute Human Immunodeficiency Virus Type 1 Subtype C Infection

2007 ◽  
Vol 81 (12) ◽  
pp. 6187-6196 ◽  
Author(s):  
E. S. Gray ◽  
P. L. Moore ◽  
I. A. Choge ◽  
J. M. Decker ◽  
F. Bibollet-Ruche ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Subtype C ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The study of the evolution and specificities of neutralizing antibodies during the course of human immunodeficiency virus type 1 (HIV-1) infection may be important in the discovery of possible targets for vaccine design. In this study, we assessed the autologous and heterologous neutralization responses of 14 HIV-1 subtype C-infected individuals, using envelope clones obtained within the first 2 months postinfection. Our data show that potent but relatively strain-specific neutralizing antibodies develop within 3 to 12 months of HIV-1 infection. The magnitude of this response was associated with shorter V1-to-V5 envelope lengths and fewer glycosylation sites, particularly in the V1-V2 region. Anti-MPER antibodies were detected in 4 of 14 individuals within a year of infection, while antibodies to CD4-induced (CD4i) epitopes developed to high titers in 12 participants, in most cases before the development of autologous neutralizing antibodies. However, neither anti-MPER nor anti-CD4i antibody specificity conferred neutralization breadth. These data provide insights into the kinetics, potency, breadth, and epitope specificity of neutralizing antibody responses in acute HIV-1 subtype C infection.

scholarly journals Induction of Primary Virus-Cross-Reactive Human Immunodeficiency Virus Type 1-Neutralizing Antibodies in Small Animals by Using an Alphavirus-Derived In Vivo Expression System

2003 ◽  
Vol 77 (5) ◽  
pp. 3119-3130 ◽  
Author(s):  
Ming Dong ◽  
Peng Fei Zhang ◽  
Franziska Grieder ◽  
James Lee ◽  
Govindaraj Krishnamurthy ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Neutralizing Activity ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Primary Virus

ABSTRACT We have studied the induction of neutralizing antibodies by in vivo expression of the human immunodeficiency virus type 1 (HIV-1) envelope by using a Venezuelan equine encephalitis virus (VEE) replicon system with mice and rabbits. The HIV-1 envelope, clone R2, has broad sensitivity to cross-reactive neutralization and was obtained from a donor with broadly cross-reactive, primary virus-neutralizing antibodies (donor of reference serum, HIV-1-neutralizing serum 2 [HNS2]). It was expressed as gp160, as secreted gp140, and as gp160ΔCT with the cytoplasmic tail deleted. gp140 was expressed in vitro at a high level and was predominantly uncleaved oligomer. gp160ΔCT was released by cells in the form of membrane-bound vesicles. gp160ΔCT induced stronger neutralizing responses than the other forms. Use of a helper plasmid for replicon particle packaging, in which the VEE envelope gene comprised a wild-type rather than a host range-adapted sequence, also enhanced immunogenicity. Neutralizing activity fractionated with immunoglobulin G. This activity was cross-reactive among a panel of five nonhomologous primary clade B strains and a Chinese clade C strain and minimally reactive against a Chinese clade E (circulating recombinant form 1) strain. The comparative neutralization of these strains by immune mouse sera was similar to the relative neutralizing effects of HNS2, and responses induced in rabbits were similar to those induced in mice. Together, these results demonstrate that neutralizing antibody responses can be induced in mice within 2 to 3 months that are similar in potency and cross-reactivity to those found in the chronically infected, long-term nonprogressive donor of HNS2. These findings support the expectation that induction of highly cross-reactive HIV-1 primary virus-neutralizing activity by vaccination may be realized.

scholarly journals Viral Phenotypes and Antibody Responses in Long-Term Survivors Infected with Attenuated Human Immunodeficiency Virus Type 1 Containing Deletions in the nef and Long Terminal Repeat Regions

2007 ◽  
Vol 81 (17) ◽  
pp. 9268-9278 ◽  
Author(s):  
Erin E. Verity ◽  
Dimitra Zotos ◽  
Kim Wilson ◽  
Catherine Chatfield ◽  
Victoria A. Lawson ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Wild Type Virus ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The Sydney Blood Bank Cohort (SBBC) consists of eight blood transfusion recipients infected with nef-attenuated human immunodeficiency virus type 1 (HIV-1) acquired from a single donor. Here, we show that viral phenotypes and antibody responses differ considerably between individual cohort members, despite the single source of infection. Replication of isolated virus varied from barely detectable to similar to that of the wild-type virus, and virus isolated from five SBBC members showed coreceptor usage signatures unique to each individual. Higher viral loads and stronger neutralizing antibody responses were associated with better-replicating viral strains, and detectable viral replication was essential for the development of strong and sustained humoral immune responses. Despite the presence of strong neutralizing antibodies in a number of SBBC members, disease progression was not prevented, and each cohort member studied displayed a unique outcome of infection with nef-attenuated HIV-1.

scholarly journals Crystallographic Definition of the Epitope Promiscuity of the Broadly Neutralizing Anti-Human Immunodeficiency Virus Type 1 Antibody 2F5: Vaccine Design Implications

2009 ◽  
Vol 83 (22) ◽  
pp. 11862-11875 ◽  
Author(s):  
Steve Bryson ◽  
Jean-Philippe Julien ◽  
Rosemary C. Hynes ◽  
Emil F. Pai
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Molecular Model ◽  
Proximal Region ◽  
Sequence Variability ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The quest to create a human immunodeficiency virus type 1 (HIV-1) vaccine capable of eliciting broadly neutralizing antibodies against Env has been challenging. Among other problems, one difficulty in creating a potent immunogen resides in the substantial overall sequence variability of the HIV envelope protein. The membrane-proximal region (MPER) of gp41 is a particularly conserved tryptophan-rich region spanning residues 659 to 683, which is recognized by three broadly neutralizing monoclonal antibodies (bnMAbs), 2F5, Z13, and 4E10. In this study, we first describe the variability of residues in the gp41 MPER and report on the invariant nature of 15 out of 25 amino acids comprising this region. Subsequently, we evaluate the ability of the bnMAb 2F5 to recognize 31 varying sequences of the gp41 MPER at a molecular level. In 19 cases, resulting crystal structures show the various MPER peptides bound to the 2F5 Fab′. A variety of amino acid substitutions outside the 664DKW666 core epitope are tolerated. However, changes at the 664DKW666 motif itself are restricted to those residues that preserve the aspartate's negative charge, the hydrophobic alkyl-π stacking arrangement between the β-turn lysine and tryptophan, and the positive charge of the former. We also characterize a possible molecular mechanism of 2F5 escape by sequence variability at position 667, which is often observed in HIV-1 clade C isolates. Based on our results, we propose a somewhat more flexible molecular model of epitope recognition by bnMAb 2F5, which could guide future attempts at designing small-molecule MPER-like vaccines capable of eliciting 2F5-like antibodies.

scholarly journals Stoichiometry of Antibody Neutralization of Human Immunodeficiency Virus Type 1

2005 ◽  
Vol 79 (6) ◽  
pp. 3500-3508 ◽  
Author(s):  
Xinzhen Yang ◽  
Svetla Kurteva ◽  
Sandra Lee ◽  
Joseph Sodroski
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Envelope Glycoprotein ◽  
Envelope Glycoproteins ◽  
Antibody Neutralization ◽  
Antibody Molecule ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The human immunodeficiency virus envelope glycoproteins function as trimers on the viral surface, where they are targeted by neutralizing antibodies. Different monoclonal antibodies neutralize human immunodeficiency virus type 1 (HIV-1) infectivity by binding to structurally and functionally distinct moieties on the envelope glycoprotein trimer. By measuring antibody neutralization of viruses with mixtures of neutralization-sensitive and neutralization-resistant envelope glycoproteins, we demonstrate that the HIV-1 envelope glycoprotein trimer is inactivated by the binding of a single antibody molecule. Virus neutralization requires essentially all of the functional trimers to be occupied by at least one antibody. This model applies to antibodies differing in neutralizing potency and to virus isolates with various neutralization sensitivities. Understanding these requirements for HIV-1 neutralization by antibodies will assist in establishing goals for an effective AIDS vaccine.

scholarly journals Profiling the Specificity of Neutralizing Antibodies in a Large Panel of Plasmas from Patients Chronically Infected with Human Immunodeficiency Virus Type 1 Subtypes B and C

2008 ◽  
Vol 82 (23) ◽  
pp. 11651-11668 ◽  
Author(s):  
James M. Binley ◽  
Elizabeth A. Lybarger ◽  
Emma T. Crooks ◽  
Michael S. Seaman ◽  
Elin Gray ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Significant Proportion ◽  
Neutralizing Activity ◽  
Subtype B ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Identifying the viral epitopes targeted by broad neutralizing antibodies (NAbs) that sometimes develop in human immunodeficiency virus type 1 (HIV-1)-infected subjects should assist in the design of vaccines to elicit similar responses. Here, we investigated the activities of a panel of 24 broadly neutralizing plasmas from subtype B- and C-infected donors using a series of complementary mapping methods, focusing mostly on JR-FL as a prototype subtype B primary isolate. Adsorption with gp120 immobilized on beads revealed that an often large but variable fraction of plasma neutralization was directed to gp120 and that in some cases, neutralization was largely mediated by CD4 binding site (CD4bs) Abs. The results of a native polyacrylamide gel electrophoresis assay using JR-FL trimers further suggested that half of the subtype B and a smaller fraction of subtype C plasmas contained a significant proportion of NAbs directed to the CD4bs. Anti-gp41 neutralizing activity was detected in several plasmas of both subtypes, but in all but one case, constituted only a minor fraction of the overall neutralization activity. Assessment of the activities of the subtype B plasmas against chimeric HIV-2 viruses bearing various fragments of the membrane proximal external region (MPER) of HIV-1 gp41 revealed mixed patterns, implying that MPER neutralization was not dominated by any single specificity akin to known MPER-specific monoclonal Abs. V3 and 2G12-like NAbs appeared to make little or no contribution to JR-FL neutralization titers. Overall, we observed significant titers of anti-CD4bs NAbs in several plasmas, but approximately two-thirds of the neutralizing activity remained undefined, suggesting the existence of NAbs with specificities unlike any characterized to date.

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