scholarly journals Production of Uninfectious Human Immunodeficiency Virus Type 1 Containing Viral Protein R Fused to a Single-Chain Antibody against Viral Integrase

1998 ◽  
Vol 72 (8) ◽  
pp. 6960-6964 ◽  
Author(s):  
Nobuo Okui ◽  
Noriko Kobayashi ◽  
Yoshihiro Kitamura
Keyword(s):  
Human Immunodeficiency Virus ◽  
Fusion Protein ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Protein ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT A single-chain antibody (scAb) against human immunodeficiency virus type 1 (HIV-1) integrase was expressed as a fusion protein of scAb and HIV-1 viral protein R (Vpr), together with the HIV-1 genome, in human 293T cells. The expression did not affect virion production much but markedly reduced the infectivity of progeny virions. The fusion protein was found to be incorporated into the virions. The incorporation appears to account for the reduced infectivity.

scholarly journals Complexity in human immunodeficiency virus type 1 (HIV-1) co-receptor usage: roles of CCR3 and CCR5 in HIV-1 infection of monocyte-derived macrophages and brain microglia

2009 ◽  
Vol 90 (3) ◽  
pp. 710-722 ◽  
Author(s):  
Lokesh Agrawal ◽  
Christina R. Maxwell ◽  
Paul J. Peters ◽  
Paul R. Clapham ◽  
Sue M. Liu ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Productive Infection ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Immunodeficiency Virus ◽  
The Central Nervous System ◽  
Hiv 1

CCR3 has been implicated as a co-receptor for human immunodeficiency virus type 1 (HIV-1), particularly in brain microglia cells. We sought to clarify the comparative roles of CCR3 and CCR5 in the central nervous system (CNS) HIV-1 infection and the potential utility of CCR3 as a target for manipulation via gene transfer. To target CCR3, we developed a single-chain antibody (SFv) and an interfering RNA (RNAi), R3-526. Coding sequences for both were cloned into Tag-deleted SV40-dervied vectors, as these vectors transduce brain microglia and monocyte-derived macrophages (MDM) highly efficiently. These anti-CCR3 transgenes were compared to SFv-CCR5, an SFv against CCR5, and RNAi-R5, an RNAi that targets CCR5, for the ability to protect primary human brain microglia and MDM from infection with peripheral and neurotropic strains of HIV-1. Downregulation of CCR3 and CCR5 by these transgenes was independent from one another. Confocal microscopy showed that CCR3 and CCR5 co-localized at the plasma membrane with each other and with CD4. Targeting either CCR5 or CCR3 largely protected both microglia and MDM from infection by many strains of HIV-1. That is, some HIV-1 strains, isolated from either the CNS or periphery, required both CCR3 and CCR5 for optimal productive infection of microglia and MDM. Some HIV-1 strains were relatively purely CCR5-tropic. None was purely CCR3-tropic. Thus, some CNS-tropic strains of HIV-1 utilize CCR5 as a co-receptor but do not need CCR3, while for other isolates both CCR3 and CCR5 may be required.

scholarly journals Design and Intracellular Activity of a Human Single-Chain Antibody to Human Immunodeficiency Virus Type 1 Conserved gp41 Epitope

2000 ◽  
Vol 74 (12) ◽  
pp. 5712-5715 ◽  
Author(s):  
Isabelle Legastelois ◽  
Claude Desgranges
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Line ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Productive Infection ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT A human lymphoid cell line (F172-D8) excreting a human immunodeficiency virus type 1 (HIV-1) anti-gp41 monoclonal antibody was used to construct a plasmid containing the cDNA of the single-chain variable fragment (scFvD8) corresponding to this antibody. A stable human osteosarcoma cell line was obtained which expressed the scFvD8 protein in the cytoplasm. Whereas a cell line transfected with a control construct (pCI-neo) was readily and productively infected with laboratory (Ba-L) or primary HIV-1 isolates, the scFvD8 cell line did not support productive infection. Binding of the virus, internalization, and reverse transcription were not altered by scFvD8 expression, but gp160 expression was dramatically reduced. These data suggest that cytoplasmic expression of this artificial single-chain antibody can interfere with gp160 expression, thereby reducing the production of mature viral envelope proteins.

scholarly journals A Novel Human Antibody against Human Immunodeficiency Virus Type 1 gp120 Is V1, V2, and V3 Loop Dependent and Helps Delimit the Epitope of the Broadly Neutralizing Antibody Immunoglobulin G1 b12

2003 ◽  
Vol 77 (12) ◽  
pp. 6965-6978 ◽  
Author(s):  
Michael B. Zwick ◽  
Robert Kelleher ◽  
Richard Jensen ◽  
Aran F. Labrijn ◽  
Meng Wang ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Human Antibody ◽  
V3 Loop ◽  
Single Chain ◽  
Single Chain Fv ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The V1/V2 and V3 loops are proximal to the CD4 binding site (CD4bs) of human immunodeficiency virus type 1 (HIV-1) gp120 and undergo conformational change upon CD4 receptor engagement by the HIV-1 envelope spike. Nearly all of the reported monoclonal antibodies (MAbs) against the CD4bs exhibit a very limited capacity to neutralize HIV-1. However, one such human MAb, immunoglobulin G1 (IgG1) b12, is uniquely able to neutralize primary isolates across subtypes with considerable potency. The molecular basis for the anti-HIV-1 activity of b12 is not fully understood but is relevant to vaccine design. Here we describe a novel human MAb, 4KG5, whose binding to monomeric gp120 is moderately enhanced by IgG1 b12. In sharp contrast, 4KG5 binding to gp120 is inhibited by soluble CD4 (sCD4) and by all other (n = 14) anti-CD4bs MAbs tested. 4KG5 is unable to recognize gp120 in which either V1, V2, or V3 has been deleted, and MAbs against the V2 or V3 loops inhibit the binding of 4KG5 to gp120. Moreover, 4KG5 is able to inhibit the binding of the CD4-induced MAbs 17b and X5 in the absence of sCD4, whereas 17b and X5 only weakly inhibit the binding of 4KG5 to gp120. Mutagenesis of gp120 provides further evidence of a discontinuous epitope of 4KG5 that is formed by the V1/V2 loop, the V3 loop, and a portion of the bridging sheet (C4). 4KG5 was isolated as a single-chain Fv from a phage display library constructed from the bone marrow of an HIV-1-seropositive subject (FDA2) whose serum neutralizes HIV-1 across subtypes. Despite its source, we observed no significant neutralization with 4KG5 against the autologous (R2) virus and several other strains of HIV-1. The results suggest a model in which antibody access to the CD4bs on the envelope spike of HIV-1 is restricted by the orientation and/or dynamics of the V1/V2 and V3 loops, and b12 avoids these restrictions.

scholarly journals Various plus unique: Viral protein U as a plurifunctional protein for HIV-1 replication

2017 ◽  
Vol 242 (8) ◽  
pp. 850-858 ◽  
Author(s):  
Andrew Soper ◽  
Guillermo Juarez-Fernandez ◽  
Hirofumi Aso ◽  
Miyu Moriwaki ◽  
Eri Yamada ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Replication ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Protein ◽  
Viral Protein U ◽  
Immunodeficiency Virus ◽  
Immunodeficiency Syndrome ◽  
Hiv 1

Human immunodeficiency virus type 1 (HIV-1), the causative agent of acquired immunodeficiency syndrome, encodes four accessory genes, one of which is viral protein U (Vpu). Recently, the study of Vpu has been of great interest. For instance, various cellular proteins are degraded (e.g. CD4) and down-modulated (e.g. tetherin) by Vpu. Vpu also antagonizes the function of tetherin and inhibits NF-κB. Moreover, Vpu is a viroporin forming ion channels and may represent a promising target for anti-HIV-1 drugs. In this review, we summarize the domains/residues that are responsible for Vpu’s functions, describe the current understanding of the role of Vpu in HIV-1-infected cells, and review the effect of Vpu on HIV-1 in replication and pathogenesis. Future investigations that simultaneously assess a combination of Vpu functions are required to clearly delineate the most important functions for viral replication. Impact statement Viral protein U (Vpu) is a unique protein encoded by human immunodeficiency virus type 1 (HIV-1) and related lentiviruses, playing multiple roles in viral replication and pathogenesis. In this review, we briefly summarize the most up-to-date knowledge of HIV-1 Vpu.

Human Single-Chain Antibodies Inhibit Replication of Human Immunodeficiency Virus Type 1 (HIV-1)

2005 ◽  
Vol 21 (10) ◽  
pp. 876-881 ◽  
Author(s):  
Fangbing Liu ◽  
Mukesh Kumar ◽  
Qiangzhong Ma ◽  
Mark Duval ◽  
David Kuhrt ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Single Chain ◽  
Single Chain Antibodies ◽  
Immunodeficiency Virus ◽  
Hiv 1

scholarly journals Neutralization of Human Immunodeficiency Virus Type 1 by sCD4-17b, a Single-Chain Chimeric Protein, Based on Sequential Interaction of gp120 with CD4 and Coreceptor

2003 ◽  
Vol 77 (5) ◽  
pp. 2859-2865 ◽  
Author(s):  
Barna Dey ◽  
Christie S. Del Castillo ◽  
Edward A. Berger
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Human Monoclonal Antibody ◽  
Chimeric Protein ◽  
Single Chain ◽  
Clade B ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT We designed a novel single-chain chimeric protein, designated sCD4-17b, for neutralization of human immunodeficiency virus type 1 (HIV-1). The recombinant protein contains domains 1 and 2 of soluble CD4 (sCD4), connected via a flexible polypeptide linker to a single-chain variable region construct of 17b, a human monoclonal antibody that targets a conserved CD4-induced epitope on gp120 overlapping the coreceptor binding region. We hypothesized that the sCD4 moiety would bind gp120 and expose the 17b epitope; the 17b moiety would then bind, thereby blocking coreceptor interaction and neutralizing infection. The sCD4-17b protein, expressed by a recombinant vaccinia virus, potently neutralized a prototypic R5 clade B primary isolate, with a 50% inhibitory concentration of 3.2 nM (0.16 μg/ml) and >95% neutralization at 32 nM (1.6 μg/ml). The individual components (sCD4 and 17b, singly or in combination) had minimal effects at these concentrations, demonstrating that the activity of sCD4-17b reflected the ability of a single chimeric molecule to bind gp120 simultaneously via two independent moieties. sCD4-17b was highly potent compared to the previously characterized broadly cross-reactive neutralizing monoclonal antibodies IgGb12, 2G12, and 2F5. Multiple primary isolates were neutralized, including two previously described as antibody resistant. Neutralization occurred for both R5 and X4 strains and was not restricted to clade B. However, several primary isolates were insensitive over the concentration range tested, despite the known presence of binding sites for both CD4 and 17b. sCD4-17b has potential utility for passive immunization against HIV-1 in several contexts, including maternal transmission, postexposure prophylaxis, and sexual transmission (topical microbicide).

scholarly journals Commitment to Apoptosis in CD4+ T Lymphocytes Productively Infected with Human Immunodeficiency Virus Type 1 Is Initiated by Lysosomal Membrane Permeabilization, Itself Induced by the Isolated Expression of the Viral Protein Nef

2007 ◽  
Vol 81 (20) ◽  
pp. 11426-11440 ◽  
Author(s):  
Mireille Laforge ◽  
Frederic Petit ◽  
Jérôme Estaquier ◽  
Anna Senik
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Lymphocytes ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Protein ◽  
Cell Subset ◽  
Membrane Permeabilization ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Primary CD4+ T lymphocytes, supporting in vitro human immunodeficiency virus type 1 (HIV-1) replication, are destined to die by apoptosis. We explored the initial molecular events that act upstream from mitochondrial dysfunction in CD4+ T lymphocytes exposed to the HIV-1LAI strain. We tracked by immunofluorescence the cells expressing the p24 viral antigen and used Percoll density gradients to isolate a nonapoptotic CD4+ T-cell subset with a high inner mitochondrial transmembrane potential (ΔΨm) but no outer mitochondrial membrane (OMM) rupture. In most p24+ (but not bystander p24−) cells of this subset, the lysosomes were undergoing limited membrane permeabilization, allowing the lysosomal efflux of cathepsins (Cat) to the cytosol. This was also induced by HIV-1 isolates from infected patients. Using pepstatin A to inhibit Cat-D enzymatic activity and Cat-D small interfering RNA to silence the Cat-D gene, we demonstrate that once released into the cytosol, Cat-D induces the conformational change of Bax and its insertion into the OMM. Inhibition of Cat-D activity/expression also conferred a transient survival advantage upon productively HIV-1-infected cells, indicating that Cat-D is an early death factor. The transfection of activated CD4+ T lymphocytes with a Nef expression vector rapidly induced the permeabilization of lysosomes and the release of Cat-D, with these two events preceding OMM rupture. These results reveal a previously undocumented mechanism in which Nef acts as an internal cytopathic factor and strongly suggest that this viral protein may behave similarly in the context of productive HIV-1 infection in CD4+ T lymphocytes.

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