scholarly journals Characterization of the Outer Domain of the gp120 Glycoprotein from Human Immunodeficiency Virus Type 1

2004 ◽  
Vol 78 (23) ◽  
pp. 12975-12986 ◽  
Author(s):  
Xinzhen Yang ◽  
Vesko Tomov ◽  
Svetla Kurteva ◽  
Liping Wang ◽  
Xinping Ren ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Envelope Glycoprotein ◽  
Antibody Responses ◽  
Outer Domain ◽  
Immunodeficiency Virus ◽  
Gp120 Glycoprotein ◽  
Hiv 1

ABSTRACT The core of the gp120 glycoprotein from human immunodeficiency virus type 1 (HIV-1) is comprised of three major structural domains: the outer domain, the inner domain, and the bridging sheet. The outer domain is exposed on the HIV-1 envelope glycoprotein trimer and contains binding surfaces for neutralizing antibodies such as 2G12, immunoglobulin G1b12, and anti-V3 antibodies. We expressed the outer domain of HIV-1YU2 gp120 as an independent protein, termed OD1. OD1 efficiently bound 2G12 and a large number of anti-V3 antibodies, indicating its structural integrity. Immunochemical studies with OD1 indicated that antibody responses against the outer domain of the HIV-1 gp120 envelope glycoprotein are rare in HIV-1-infected human sera that potently neutralize the virus. Surprisingly, such outer-domain-directed antibody responses are commonly elicited by immunization with recombinant monomeric gp120. Immunization with soluble, stabilized HIV-1 envelope glycoprotein trimers elicited antibody responses that more closely resembled those in the sera of HIV-1-infected individuals. These results underscore the qualitatively different humoral immune responses elicited during natural infection and after gp120 vaccination and help to explain the failure of gp120 as an effective vaccine.

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 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 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 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 Cellular Immune Responses in Asymptomatic Human Immunodeficiency Virus Type 1 (HIV-1) Infection and Effects of Vaccination with Recombinant Envelope Glycoprotein of HIV-1

2006 ◽  
Vol 13 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Geoffrey J. Gorse ◽  
Ramona E. Simionescu ◽  
Gira B. Patel
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Envelope Glycoprotein ◽  
Lymphocyte Proliferation ◽  
Immunodeficiency Virus ◽  
Ifn Γ ◽  
Hiv 1

ABSTRACT Effects of human immunodeficiency virus type 1 (HIV-1) recombinant envelope glycoprotein vaccines on cell-mediated immune (CMI) responses were assessed in HIV-1-infected patients. Asymptomatic, antiretroviral-treatment-naïve, HIV-1-infected patients with CD4+ T-cell counts greater than 400/μl received multiple intramuscular injections of HIV-1 IIIB recombinant envelope glycoprotein (rgp160) vaccine or HIV-1 MN recombinant envelope glycoprotein (rgp120) vaccine (eight patients, referred to as the HIV-1 vaccinees) or placebo or hepatitis B vaccine (three patients, referred to as the controls). Lymphocyte proliferation in response to HIV-1 envelope glycoproteins, both homologous and heterologous to the HIV-1 immunogens, was absent prior to study treatment in all patients but increased significantly during the vaccination series and after the final vaccination in HIV-1 vaccinees (P < 0.05) and remained absent in control patients. In flow cytometric analyses of intracellular cytokines, T-cell receptor stimulation with an anti-CD3 antibody induced gamma interferon (IFN-γ) expression by activated CD4+ and CD8+ lymphocytes at greater frequencies than did stimulation with recombinant envelope glycoprotein and p24 of HIV-1 (P< 0.05). Mean frequencies of HIV-1 envelope glycoprotein-stimulated, activated intracellularIFN-γ-producing CD4+ and CD8+ lymphocytes and of interleukin-2-producing CD4+ lymphocytes did not increase after vaccination, but cytokine-producing cells were detectable in some patients. Comparing pre- to post-HIV-1 vaccination time points, changes in frequencies of activated, IFN-γ-producing CD4+ cells correlated inversely with changes in lymphocyte proliferation in response to recombinant envelope glycoprotein in HIV-1 vaccinees (P < 0.05). Increased CMI responses to HIV-1 envelope glycoprotein measured by lymphocyte proliferation were associated with HIV-1 recombinant envelope glycoprotein vaccines.

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