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Title: Antigenicity and immunogenicity of HIV-1 consensus subtype B envelope glycoproteins

Abstract

'Centralized' (ancestral and consensus) HIV-1 envelope immunogens induce broadly cross-reactive T cell responses in laboratory animals; however, their potential to elicit cross-reactive neutralizing antibodies has not been fully explored. Here, we report the construction of a panel of consensus subtype B (ConB) envelopes and compare their biologic, antigenic, and immunogenic properties to those of two wild-type Env controls from individuals with early and acute HIV-1 infection. Glycoprotein expressed from full-length (gp160), uncleaved (gp160-UNC), truncated (gp145), and N-linked glycosylation site deleted (gp160-201N/S) versions of the ConB env gene were packaged into virions and, except for the fusion defective gp160-UNC, mediated infection via the CCR5 co-receptor. Pseudovirions containing ConB Envs were sensitive to neutralization by patient plasma and monoclonal antibodies, indicating the preservation of neutralizing epitopes found in contemporary subtype B viruses. When used as DNA vaccines in guinea pigs, ConB and wild-type env immunogens induced appreciable binding, but overall only low level neutralizing antibodies. However, all four ConB immunogens were significantly more potent than one wild-type vaccine at eliciting neutralizing antibodies against a panel of tier 1 and tier 2 viruses, and ConB gp145 and gp160 were significantly more potent than both wild-type vaccines at inducing neutralizing antibodies against tier 1more » viruses. Thus, consensus subtype B env immunogens appear to be at least as good as, and in some instances better than, wild-type B env immunogens at inducing a neutralizing antibody response, and are amenable to further improvement by specific gene modifications.« less

Authors:
; ; ; ; ; ; ; ;  [1]; ;  [2]; ;  [3];  [4];  [5];  [6];  [7]
  1. Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)
  2. Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)
  3. Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710 (United States)
  4. Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)|[Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)|[Howard Hughes Medical Institute, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)
  5. Department of Mathematics, University of Manchester Institute of Technology, Manchester M601QD (United Kingdom)
  6. Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)|[Santa Fe Institute, Santa Fe, NM 87501 (United States)
  7. Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)|[Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294 (United States). E-mail: bhahn@uab.edu
Publication Date:
OSTI Identifier:
20977006
Resource Type:
Journal Article
Resource Relation:
Journal Name: Virology; Journal Volume: 360; Journal Issue: 1; Other Information: DOI: 10.1016/j.virol.2006.10.017; PII: S0042-6822(06)00748-3; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; AIDS VIRUS; DNA; GENES; GLYCOPROTEINS; GUINEA PIGS; LABORATORY ANIMALS; MONOCLONAL ANTIBODIES; PATIENTS; RECEPTORS; VACCINES

Citation Formats

Kothe, Denise L., Decker, Julie M., Li Yingying, Weng Zhiping, Bibollet-Ruche, Frederic, Zammit, Kenneth P., Salazar, Maria G., Chen, Yalu, Salazar-Gonzalez, Jesus F., Moldoveanu, Zina, Mestecky, Jiri, Gao Feng, Haynes, Barton F., Shaw, George M., Muldoon, Mark, Korber, Bette T.M., and Hahn, Beatrice H.. Antigenicity and immunogenicity of HIV-1 consensus subtype B envelope glycoproteins. United States: N. p., 2007. Web. doi:10.1016/j.virol.2006.10.017.
Kothe, Denise L., Decker, Julie M., Li Yingying, Weng Zhiping, Bibollet-Ruche, Frederic, Zammit, Kenneth P., Salazar, Maria G., Chen, Yalu, Salazar-Gonzalez, Jesus F., Moldoveanu, Zina, Mestecky, Jiri, Gao Feng, Haynes, Barton F., Shaw, George M., Muldoon, Mark, Korber, Bette T.M., & Hahn, Beatrice H.. Antigenicity and immunogenicity of HIV-1 consensus subtype B envelope glycoproteins. United States. doi:10.1016/j.virol.2006.10.017.
Kothe, Denise L., Decker, Julie M., Li Yingying, Weng Zhiping, Bibollet-Ruche, Frederic, Zammit, Kenneth P., Salazar, Maria G., Chen, Yalu, Salazar-Gonzalez, Jesus F., Moldoveanu, Zina, Mestecky, Jiri, Gao Feng, Haynes, Barton F., Shaw, George M., Muldoon, Mark, Korber, Bette T.M., and Hahn, Beatrice H.. Fri . "Antigenicity and immunogenicity of HIV-1 consensus subtype B envelope glycoproteins". United States. doi:10.1016/j.virol.2006.10.017.
@article{osti_20977006,
title = {Antigenicity and immunogenicity of HIV-1 consensus subtype B envelope glycoproteins},
author = {Kothe, Denise L. and Decker, Julie M. and Li Yingying and Weng Zhiping and Bibollet-Ruche, Frederic and Zammit, Kenneth P. and Salazar, Maria G. and Chen, Yalu and Salazar-Gonzalez, Jesus F. and Moldoveanu, Zina and Mestecky, Jiri and Gao Feng and Haynes, Barton F. and Shaw, George M. and Muldoon, Mark and Korber, Bette T.M. and Hahn, Beatrice H.},
abstractNote = {'Centralized' (ancestral and consensus) HIV-1 envelope immunogens induce broadly cross-reactive T cell responses in laboratory animals; however, their potential to elicit cross-reactive neutralizing antibodies has not been fully explored. Here, we report the construction of a panel of consensus subtype B (ConB) envelopes and compare their biologic, antigenic, and immunogenic properties to those of two wild-type Env controls from individuals with early and acute HIV-1 infection. Glycoprotein expressed from full-length (gp160), uncleaved (gp160-UNC), truncated (gp145), and N-linked glycosylation site deleted (gp160-201N/S) versions of the ConB env gene were packaged into virions and, except for the fusion defective gp160-UNC, mediated infection via the CCR5 co-receptor. Pseudovirions containing ConB Envs were sensitive to neutralization by patient plasma and monoclonal antibodies, indicating the preservation of neutralizing epitopes found in contemporary subtype B viruses. When used as DNA vaccines in guinea pigs, ConB and wild-type env immunogens induced appreciable binding, but overall only low level neutralizing antibodies. However, all four ConB immunogens were significantly more potent than one wild-type vaccine at eliciting neutralizing antibodies against a panel of tier 1 and tier 2 viruses, and ConB gp145 and gp160 were significantly more potent than both wild-type vaccines at inducing neutralizing antibodies against tier 1 viruses. Thus, consensus subtype B env immunogens appear to be at least as good as, and in some instances better than, wild-type B env immunogens at inducing a neutralizing antibody response, and are amenable to further improvement by specific gene modifications.},
doi = {10.1016/j.virol.2006.10.017},
journal = {Virology},
number = 1,
volume = 360,
place = {United States},
year = {Fri Mar 30 00:00:00 EDT 2007},
month = {Fri Mar 30 00:00:00 EDT 2007}
}
  • We previously reported that an envelope (Env) glycoprotein immunogen (o-gp140{delta}V2SF162) containing a partial deletion in the second variable loop (V2) derived from the R5-tropic HIV-1 isolate SF162 partially protected vaccinated rhesus macaques against pathogenic SHIV{sub SF162P4} virus. Extending our studies to subtype C isolate TV1, we have purified o-gp140{delta}V2TV1 (subtype C {delta}V2 trimer) to homogeneity, performed glycosylation analysis, and determined its ability to bind CD4, as well as a panel of well-characterized neutralizing monoclonal antibodies (mAb). In general, critical epitopes are preserved on the subtype C {delta}V2 trimer; however, we did not observe significant binding for the b12 mAb. Themore » molecular mass of subtype C {delta}V2 trimer was found to be 450 kDa, and the hydrodynamic radius was found to be 10.87 nm. Our data suggest that subtype C {delta}V2 trimer binds to CD4 with an affinity comparable to o-gp140{delta}V2SF162 (subtype B {delta}V2 trimer). Using isothermal titration calorimetric (ITC) analysis, we demonstrated that all three CD4 binding sites (CD4-BS) in both subtype C and B trimers are exposed and accessible. However, compared to subtype B trimer, the three CD4-BS in subtype C trimer have different affinities for CD4, suggesting a cooperativity of CD4 binding in subtype C trimer but not in subtype B trimer. Negative staining electron microscopy of the subtype C {delta}V2 trimer has demonstrated that it is in fact a trimer. These results highlight the importance of studying subtype C Env, and also of developing appropriate subtype C-specific reagents that may be used for better immunological characterization of subtype C Env for developing an AIDS vaccine.« less
  • The external domains of the HIV-1 envelope glycoprotein (gp120 and the gp41 ectodomain, collectively known as gp140) contain all known viral neutralization epitopes. Various strategies have been used to create soluble trimers of the envelope to mimic the structure of the native viral protein, including mutation of the gp120-gp41 cleavage site, introduction of disulfide bonds, and fusion to heterologous trimerization motifs. We compared the effects on quaternary structure, antigenicity, and immunogenicity of three such motifs: T4 fibritin, a GCN4 variant, and the Escherichia coli aspartate transcarbamoylase catalytic subunit. Fusion of each motif to the C-terminus of a noncleavable JRCSF gp140(-)more » envelope protein led to enhanced trimerization but had limited effects on the antigenic profile and CD4-binding ability of the trimers. Immunization of rabbits provided no evidence that the trimerized gp140(-) constructs induced significantly improved neutralizing antibodies to several HIV-1 pseudoviruses, compared to gp140 lacking a trimerization motif. However, modest differences in both binding specificity and neutralizing antibody responses were observed among the various immunogens.« less
  • Here, the extraordinary genetic diversity of the HIV-1 envelope spike [Env; trimeric (gp160) 3, cleaved to (gp120/gp41) 3] poses challenges for vaccine development. Envs of different clinical isolates exhibit different sensitivities to antibody-mediated neutralization. Envs of difficult-to-neutralize viruses are thought to be more stable and conformationally homogeneous trimers than those of easy-to-neutralize viruses, thereby providing more effective concealment of conserved, functionally critical sites. In this study we have characterized the antigenic properties of an Env derived from one of the most neutralization-resistant HIV-1 isolates, CH120.6. Sequence variation at neutralizing epitopes does not fully account for its exceptional resistance to antibodies.more » The full-length, membrane-bound CH120.6 Env is indeed stable and conformationally homogeneous. Its antigenicity correlates closely with its neutralization sensitivity, and major changes in antigenicity upon CD4 engagement appear to be restricted to the coreceptor site. The CH120.6 gp140 trimer, the soluble and uncleaved ectodomain of (gp160) 3, retains many antigenic properties of the intact Env, consistent with a conformation close to that of Env spikes on a virion, whereas its monomeric gp120 exposes many nonneutralizing or strain-specific epitopes. Thus, trimer organization and stability are important determinants not only for occluding many epitopes but also for conferring resistance to neutralization by all but a small set of antibodies. Env preparations derived from neutralization-resistant viruses may induce irrelevant antibody responses less frequently than do other Envs and may be excellent templates for developing soluble immunogens.« less
  • The present invention relates, in general, to an immunogen and, in particular, to an immunogen for inducing antibodies that neutralizes a wide spectrum of HIV primary isolates and/or to an immunogen that induces a T cell immune response. The invention also relates to a method of inducing anti-HIV antibodies, and/or to a method of inducing a T cell immune response, using such an immunogen. The invention further relates to nucleic acid sequences encoding the present immunogens.
  • Functional studies of HIV-1 envelope glycoproteins (Envs) commonly include the generation of pseudoviruses, which are produced by co-transfection of rev-vpu-env cassettes with an env-deficient provirus. Here, we describe six Env constructs from transmitted/founder HIV-1 that were defective in the pseudotyping assay, although two produced infectious virions when expressed from their cognate proviruses. All of these constructs exhibited an unusual gene arrangement in which the first exon of rev (rev1) and vpu were in the same reading frame without an intervening stop codon. Disruption of the rev1-vpu fusion gene by frameshift mutation, stop codon, or abrogation of the rev initiation codonmore » restored pseudovirion infectivity. Introduction of the fusion gene into wildtype Env cassettes severely compromised their function. The defect was not due to altered env and rev transcription or a dominant negative effect of the expressed fusion protein, but seemed to be caused by inefficient translation at the env initiation codon. Although the rev1-vpu polymorphism affects Env expression only in vitro, it can cause problems in studies requiring Env complementation, such as analyses of co-receptor usage and neutralization properties, since 3% of subtype A, 20% of subtype C and 5% of CRF01{sub A}/E viruses encode the fusion gene. A solution is to eliminate the rev initiation codon when amplifying rev-vpu-env cassettes since this increases Env expression irrespective of the presence of the polymorphism.« less