scholarly journals Role of envelope glycoprotein carbohydrate in human immunodeficiency virus (HIV) infectivity and virus-induced cell fusion.

1986 ◽  
Vol 164 (6) ◽  
pp. 2101-2106 ◽  
Author(s):  
J Lifson ◽  
S Coutré ◽  
E Huang ◽  
E Engleman
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Fusion ◽  
Envelope Glycoprotein ◽  
Lectin Binding ◽  
Recombinant Vaccinia Virus ◽  
Viral Envelope ◽  
Envelope Gene ◽  
Con A ◽  
Immunodeficiency Virus ◽  
Hiv Envelope

Human immunodeficiency virus (HIV) envelope glycoprotein interactions with cell surface CD4 are involved in both virion infectivity and virally mediated cell fusion. D-mannose-specific lectins such as Con A specifically blocked virion infectivity and cell fusion. Studies with a recombinant vaccinia virus containing the HIV envelope gene demonstrated that Con A-mediated inhibition of HIV-induced fusion involved lectin binding to the viral envelope glycoprotein. These results indicate the importance of envelope glycosylation in the pathobiology of HIV infection, and suggest potential mechanisms for interfering with HIV infectivity and cytopathology.

scholarly journals Destruction of primary CD4+ T cells by cell–cell interaction in human immunodeficiency virus type 1 infection in vitro

2000 ◽  
Vol 81 (8) ◽  
pp. 1907-1911 ◽  
Author(s):  
Hartmut Stocker ◽  
Carsten Scheller ◽  
Christian Jassoy
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Cell Fusion ◽  
Envelope Glycoprotein ◽  
Cell Interaction ◽  
Viral Envelope ◽  
Immunodeficiency Virus

Infection of CD4+ T lymphocytes with human immunodeficiency virus (HIV) in vitro is accompanied by extensive cytopathicity. The mechanism of cell death is unclear, but may be related to expression of the viral envelope glycoprotein. Here, it is demonstrated that T cell destruction in primary T cells occurs upon contact of infected with uninfected lymphocytes. Cell death was due to the interaction of the envelope glycoprotein with CD4 and subsequent fusion of the cells. Agents that interfered with cell-to-cell fusion such as a monoclonal antibody to CD4 and the peptide T20 prevented T cell death and depletion. In contrast, single-cell lysis due to expression and intracellular processing of the envelope glycoprotein was insignificant. These results suggest that cell-to-cell fusion and concomitant rapid cell death promote the depletion of T cells in HIV-infected individuals.

scholarly journals An Unrelated Monoclonal Antibody Neutralizes Human Immunodeficiency Virus Type 1 by Binding to an Artificial Epitope Engineered in a Functionally Neutral Region of the Viral Envelope Glycoproteins

2005 ◽  
Vol 79 (9) ◽  
pp. 5616-5624 ◽  
Author(s):  
Xinping Ren ◽  
Joseph Sodroski ◽  
Xinzhen Yang
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Envelope Glycoprotein ◽  
Virus Entry ◽  
Neutralizing Antibody ◽  
Viral Envelope ◽  
Epitope Tag ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Neutralizing antibodies often recognize regions of viral envelope glycoproteins that play a role in receptor binding or other aspects of virus entry. To address whether this is a necessary feature of a neutralizing antibody, we identified the V4 region of the gp120 envelope glycoprotein of human immunodeficiency virus type 1 (HIV-1) as a sequence that is tolerant of drastic change and thus appears to play a negligible role in envelope glycoprotein function. An artificial epitope tag was inserted into the V4 region without a significant effect on virus entry or neutralization by antibodies that recognize HIV-1 envelope glycoprotein sequences. An antibody directed against the artificial epitope tag was able to neutralize the modified, but not the wild-type, HIV-1. Thus, the specific target of a neutralizing antibody need not contribute functionally to the process of virus entry.

scholarly journals Envelope Gene of the Human Endogenous Retrovirus HERV-W Encodes a Functional Retrovirus Envelope

2001 ◽  
Vol 75 (7) ◽  
pp. 3488-3489 ◽  
Author(s):  
Dong Sung An ◽  
Yi-ming Xie ◽  
Irvin S. Y. Chen
Keyword(s):  
Human Immunodeficiency Virus ◽  
Functional Properties ◽  
Envelope Glycoprotein ◽  
Endogenous Retrovirus ◽  
Human Endogenous Retrovirus ◽  
Envelope Gene ◽  
Membrane Glycoprotein ◽  
Herv Family ◽  
Immunodeficiency Virus

ABSTRACT A member of the human endogenous retrovirus (HERV) family termed HERV-W encodes a highly fusogenic membrane glycoprotein that appears to be expressed specifically in the placenta. It is unclear whether the glycoproteins of the HERVs can serve as functional retrovirus envelope proteins to confer infectivity on retrovirus particles. We found that the HERV-W envelope glycoprotein can form pseudotypes with human immunodeficiency virus type 1 virions and confers tropism for CD4-negative cells. Thus, the HERV-W env gene represents the first HERV env gene demonstrated to encode the functional properties of a retrovirus envelope glycoprotein.

scholarly journals Variants selected by treatment of human immunodeficiency virus-infected cells with an immunotoxin.

1990 ◽  
Vol 172 (3) ◽  
pp. 745-757 ◽  
Author(s):  
S H Pincus ◽  
K Wehrly ◽  
E Tschachler ◽  
S F Hayes ◽  
R S Buller ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Surface ◽  
Reverse Transcriptase ◽  
Selection Process ◽  
Parental Cell ◽  
Parental Cell Line ◽  
Envelope Gene ◽  
Immunodeficiency Virus ◽  
Human T Lymphocyte ◽  
Hiv Envelope

An immunotoxin has been made by coupling anti-human immunodeficiency virus (HIV) envelope antibody 907 to ricin A chain (907-RAC). 907 recognizes an epitope within the immunodominant PB-1 loop of gp120. Variant cells were selected by cloning persistently infected H9/human T lymphocyte virus IIIB cells in the presence of the immunotoxin. Clones resistant to 907-RAC arose at a frequency of 0.1-1.0%. Seven clones were selected for intensive analysis. When studied, these clones fell into two distinct groups, members of which appeared to be identical, suggesting that the variation arose before the selection process. In contrast to the parent cells, none of the cloned variants produced infectious HIV. The first set of clones, designated the "E" variants, expressed decreased levels of the HIV envelope on the cell surface. However, levels of intracellular HIV antigens and reverse transcriptase were equal to or greater than that of the parental cell line. Radioimmunoprecipitation demonstrated that the gp160 was truncated to 145 kD (gp120 was normal length), capable of binding to CD4, and, unlike normal gp160, was released in its unprocessed form into the cellular supernatant. Sequence analysis demonstrated that a deletion at codon 687 of the envelope gene resulted in the production of this truncated protein. Ultrastructural analysis of E variants demonstrated some budding forms of virus, but also large numbers of HIV within intracellular vesicles. The second set of variants, the "F" series, produced no HIV antigens, reverse transcriptase, nor was there ultrastructural evidence of virus. However, proviral DNA was present. Virus could not be induced with agents known to activate latent HIV. These cells also lacked cell surface CD4 and could not be infected with HIV. These studies demonstrate that variation in HIV can affect the phenotype of the cells carrying the altered virus, allowing for escape from immunologic destruction. The E variants may serve as prototypes for attenuated HIV, which could be used as a vaccine. We have reconstructed the mutation found in the E variants within the infectious HIV clone HXB-2 and demonstrated that the resulting virus retains its noninfectious phenotype.

scholarly journals Antigenicity and Immunogenicity of a Synthetic Human Immunodeficiency Virus Type 1 Group M Consensus Envelope Glycoprotein

2005 ◽  
Vol 79 (2) ◽  
pp. 1154-1163 ◽  
Author(s):  
Feng Gao ◽  
Eric A. Weaver ◽  
Zhongjing Lu ◽  
Yingying Li ◽  
Hua-Xin Liao ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Vaccine Development ◽  
Recombinant Vaccinia Virus ◽  
Genetic Distances ◽  
Envelope Gene ◽  
Subtype C ◽  
Subtype B ◽  
Field Virus ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Genetic variation of human immunodeficiency virus (HIV-1) represents a major obstacle for AIDS vaccine development. To decrease the genetic distances between candidate immunogens and field virus strains, we have designed and synthesized an artificial group M consensus env gene (CON6 gene) to be equidistant from contemporary HIV-1 subtypes and recombinants. This novel envelope gene expresses a glycoprotein that binds soluble CD4, utilizes CCR5 but not CXCR4 as a coreceptor, and mediates HIV-1 entry. Key linear, conformational, and glycan-dependent monoclonal antibody epitopes are preserved in CON6, and the glycoprotein is recognized equally well by sera from individuals infected with different HIV-1 subtypes. When used as a DNA vaccine followed by a recombinant vaccinia virus boost in BALB/c mice, CON6 env gp120 and gp140CF elicited gamma interferon-producing T-cell responses that recognized epitopes within overlapping peptide pools from three HIV-1 Env proteins, CON6, MN (subtype B), and Chn19 (subtype C). Sera from guinea pigs immunized with recombinant CON6 Env gp120 and gp140CF glycoproteins weakly neutralized selected HIV-1 primary isolates. Thus, the computer-generated “consensus” env genes are capable of expressing envelope glycoproteins that retain the structural, functional, and immunogenic properties of wild-type HIV-1 envelopes.

scholarly journals Expression of the Extracellular Domain of the Human Immunodeficiency Virus Type 1 Envelope Protein and Its Fusion with β-Galactosidase in Saccharomyces cerevisiae

1998 ◽  
Vol 5 (4) ◽  
pp. 592-594 ◽  
Author(s):  
Wei-Feng Liu ◽  
Dong Gao ◽  
Zu-Nong Wang
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Human Immunodeficiency Virus ◽  
Envelope Glycoprotein ◽  
Shuttle Vector ◽  
Total Protein Content ◽  
Envelope Gene ◽  
Cell Extracts ◽  
Immunodeficiency Virus ◽  
Cloned Gene

ABSTRACT Two envelope glycoprotein gene fragments were cloned from the proviral genome of the HXB2 isolate of human immunodeficiency virus (HIV). For the production of the two domains of the envelope gene product these cloned gene fragments were inserted into anEscherichia coli-yeast inducible shuttle vector fused to the galactokinase (GAL1) promoter. Cell extracts from strains ofSaccharomyces cerevisiae harboring these two vectors (pYENV1 and pYENV2) were found to contain a specific protein with a size of 50 kDa when induced by galactose, while the protein could not be detected in extracts from control cells containing only the E. coli-yeast vector in the presence of galactose. Furthermore, another expression plasmid coding for fusion proteins from the majority of the external envelope glycoprotein (gp120) moiety and a large part of the β-galactosidase was constructed. Antibodies from HIV type 1-positive sera could react with recombinant fusion polypeptides. Transformants could produce this fusion protein to a level of about 1.6% of the total protein content, as deduced from β-galactosidase activity.

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