scholarly journals Persistent Infection with Primate Foamy Virus Type 1 Increases Human Immunodeficiency Virus Type 1 Cell Binding via a Bet-Independent Mechanism

2004 ◽  
Vol 78 (20) ◽  
pp. 11405-11410 ◽  
Author(s):  
Cecile Schiffer ◽  
Charles-Henri Lecellier ◽  
Abdelkrim Mannioui ◽  
Nathalie Felix ◽  
Elisabeth Nelson ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Foamy Virus ◽  
Virus Transmission ◽  
Target Cells ◽  
Virus Attachment ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT We report that human T cells persistently infected with primate foamy virus type 1 (PFV-1) display an increased capacity to bind human immunodeficiency virus type 1 (HIV-1), resulting in increased cell permissiveness to HIV-1 infection and enhanced cell-to-cell virus transmission. This phenomenon is independent of HIV-1 receptor, CD4, and it is not related to PFV-1 Bet protein expression. Increased virus attachment is specifically inhibited by heparin, indicating that it should be mediated by interactions with heparan sulfate glycosaminoglycans expressed on the target cells. Given that both viruses infect similar animal species, the issue of whether coinfection with primate foamy viruses interferes with the natural course of lentivirus infections in nonhuman primates should be considered.

scholarly journals Antibody-Mediated Neutralization of Primary Human Immunodeficiency Virus Type 1 Isolates: Investigation of the Mechanism of Inhibition

2001 ◽  
Vol 75 (5) ◽  
pp. 2235-2245 ◽  
Author(s):  
Catherine Spenlehauer ◽  
André Kirn ◽  
Anne-Marie Aubertin ◽  
Christiane Moog
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Cell Line ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Target Cells ◽  
Virus Attachment ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) neutralization occurs when specific antibodies, mainly those directed against the envelope glycoproteins, inhibit infection, most frequently by preventing the entry of the virus into target cells. However, the precise mechanisms of neutralization remain unclear. Previous studies, mostly with cell lines, have produced conflicting results involving either the inhibition of virus attachment or interference with postbinding events. In this study, we investigated the mechanisms of neutralization by immune sera and compared the inhibition of peripheral blood mononuclear cells (PBMC) infection by HIV-1 primary isolates (PI) with the inhibition of T-cell line infection by T-cell line-adapted (TCLA) strains. We followed the kinetics of neutralization to determine at which step of the viral cycle the antibodies act. We found that neutralization of the TCLA strain HIV-1MN/MT-4 required an interaction between antibodies and cell-free virions before the addition of MT-4 cells, whereas PI were neutralized even after adsorption onto PBMC. In addition, the dose-dependent inhibition of HIV-1MN binding to MT-4 cells was strongly correlated with serum-induced neutralization. In contrast, neutralizing sera did not reduce the adhesion of PI to PBMC. Postbinding inhibition was also detected for HIV-1MN produced by and infecting PBMC, demonstrating that the mechanism of neutralization depends on the target cell used in the assay. Finally, we considered whether the different mechanisms of neutralization may reflect the recognition of qualitatively different epitopes on the surface of PI and HIV-1MN or whether they reflect differences in virus attachment to PBMC and MT-4 cells.

scholarly journals Discovery and Characterization of Vicriviroc (SCH 417690), a CCR5 Antagonist with Potent Activity against Human Immunodeficiency Virus Type 1

2005 ◽  
Vol 49 (12) ◽  
pp. 4911-4919 ◽  
Author(s):  
Julie M. Strizki ◽  
Cecile Tremblay ◽  
Serena Xu ◽  
Lisa Wojcik ◽  
Nicole Wagner ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Calcium Flux ◽  
Ccr5 Antagonist ◽  
Target Cells ◽  
Gene Transcript ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Inhibiting human immunodeficiency virus type 1 (HIV-1) infection by blocking the host cell coreceptors CCR5 and CXCR4 is an emerging strategy for antiretroviral therapy. Currently, several novel coreceptor inhibitors are being developed in the clinic, and early results have proven promising. In this report, we describe a novel CCR5 antagonist, vicriviroc (formerly SCH-D or SCH 417690), with improved antiviral activity and pharmacokinetic properties compared to those of SCH-C, a previously described CCR5 antagonist. Like SCH-C, vicriviroc binds specifically to the CCR5 receptor and prevents infection of target cells by CCR5-tropic HIV-1 isolates. In antiviral assays, vicriviroc showed potent, broad-spectrum activity against genetically diverse and drug-resistant HIV-1 isolates and was consistently more active than SCH-C in inhibiting viral replication. This compound demonstrated synergistic anti-HIV activity in combination with drugs from all other classes of approved antiretrovirals. Competition binding assays revealed that vicriviroc binds with higher affinity to CCR5 than SCH-C. Functional assays, including inhibition of calcium flux, guanosine 5′-[35S]triphosphate exchange, and chemotaxis, confirmed that vicriviroc acts as a receptor antagonist by inhibiting signaling of CCR5 by chemokines. Finally, vicriviroc demonstrated diminished affinity for the human ether a-go-go related gene transcript ion channel compared to SCH-C, suggesting a reduced potential for cardiac effects. Vicriviroc represents a promising new candidate for the treatment of HIV-1 infection.

scholarly journals Differential Transmission of Human Immunodeficiency Virus Type 1 by Distinct Subsets of Effector Dendritic Cells

2002 ◽  
Vol 76 (15) ◽  
pp. 7812-7821 ◽  
Author(s):  
Rogier W. Sanders ◽  
Esther C. de Jong ◽  
Christopher E. Baldwin ◽  
Joost H. N. Schuitemaker ◽  
Martien L. Kapsenberg ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Dendritic Cells ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Virus Transmission ◽  
Viral Envelope ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Dendritic cells (DC) support human immunodeficiency virus type 1 (HIV-1) transmission by capture of the virus particle in the mucosa and subsequent transport to the draining lymph node, where HIV-1 is presented to CD4+ Th cells. Virus transmission involves a high-affinity interaction between the DC-specific surface molecule DC-SIGN and the viral envelope glycoprotein gp120 and subsequent internalization of the virus, which remains infectious. The mechanism of viral transmission from DC to T cells is currently unknown. Sentinel immature DC (iDC) develop into Th1-promoting effector DC1 or Th2-promoting DC2, depending on the activation signals. We studied the ability of these effector DC subsets to support HIV-1 transmission in vitro. Compared with iDC, virus transmission is greatly upregulated for the DC1 subset, whereas DC2 cells are inactive. Increased transmission by DC1 correlates with increased expression of ICAM-1, and blocking studies confirm that ICAM-1 expression on DC is important for HIV transmission. The ICAM-1-LFA-1 interaction is known to be important for immunological cross talk between DC and T cells, and our results indicate that this cell-cell contact is exploited by HIV-1 for efficient transmission.

scholarly journals Impaired Processing and Presentation of Cytotoxic-T-Lymphocyte (CTL) Epitopes Are Major Escape Mechanisms from CTL Immune Pressure in Human Immunodeficiency Virus Type 1 Infection

2004 ◽  
Vol 78 (3) ◽  
pp. 1324-1332 ◽  
Author(s):  
Yoshiyuki Yokomaku ◽  
Hideka Miura ◽  
Hiroko Tomiyama ◽  
Ai Kawana-Tachikawa ◽  
Masafumi Takiguchi ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Target Cells ◽  
Ctl Epitopes ◽  
Field Isolates ◽  
Ctl Epitope ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Investigating escape mechanisms of human immunodeficiency virus type 1 (HIV-1) from cytotoxic T lymphocytes (CTLs) is essential for understanding the pathogenesis of HIV-1 infection and developing effective vaccines. To study the processing and presentation of known CTL epitopes, we prepared Epstein-Barr virus-transformed B cells that endogenously express the gag gene of six field isolates by adopting an env/nef-deletion HIV-1 vector pseudotyped with vesicular stomatitis virus G protein and then tested them for the recognition by Gag epitope-specific CTL lines or clones. We observed that two field variants, SLFNTVAVL and SVYNTVATL, of an A*0201-restricted Gag CTL epitope SLYNTVATL, and three field variants, KYRLKHLVW, QYRLKHIVW, and RYRLKHLVW, of an A24-restricted Gag CTL epitope KYKLKHIVW escaped from being killed by the CTL lines, despite the fact that they were recognized when the synthetic peptides corresponding to these variant sequences were exogenously loaded onto the target cells. Thus, their escape is likely due to the changes that occur during the processing and presentation of epitopes in the infected cells. Mutations responsible for this mode of escape were located within the epitope regions rather than the flanking regions, and such mutations did not influence the virus replication. The results suggest that the impaired antigen processing and presentation often occur in HIV-1 field isolates and thus are one of the major mechanisms that enable HIV-1 to escape from CTL recognition. We emphasize the importance of testing HIV-1 variants in an endogenous expression system.

scholarly journals Genetic Recombination of Human Immunodeficiency Virus Type 1 in One Round of Viral Replication: Effects of Genetic Distance, Target Cells, Accessory Genes, and Lack of High Negative Interference in Crossover Events

2005 ◽  
Vol 79 (3) ◽  
pp. 1666-1677 ◽  
Author(s):  
Terence D. Rhodes ◽  
Olga Nikolaitchik ◽  
Jianbo Chen ◽  
Douglas Powell ◽  
Wei-Shau Hu
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Recombination Rate ◽  
Target Cells ◽  
Recombination Rates ◽  
Negative Interference ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Recombination is a major mechanism that generates variation in populations of human immunodeficiency virus type 1 (HIV-1). Mutations that confer replication advantages, such as drug resistance, often cluster within regions of the HIV-1 genome. To explore how efficiently HIV-1 can assort markers separated by short distances, we developed a flow cytometry-based system to study recombination. Two HIV-1-based vectors were generated, one encoding the mouse heat-stable antigen gene and green fluorescent protein gene (GFP), and the other encoding the mouse Thy-1 gene and GFP. We generated derivatives of both vectors that contained nonfunctional GFP inactivated by different mutations. Recombination in the region between the two inactivating mutations during reverse transcription could yield a functional GFP. With this system, we determined that the recombination rates of markers separated by 588, 300, 288, and 103 bp in one round of viral replication are 56, 38, 31, and 12%, respectively, of the theoretical maximum measurable recombination rate. Statistical analyses revealed that at these intervals, recombination rates and marker distances have a near-linear relationship that is part of an overall quadratic fit. Additionally, we examined the segregation of three markers within 600 bp and concluded that HIV-1 crossover events do not exhibit high negative interference. We also examined the effects of target cells and viral accessory proteins on recombination rate. Similar recombination rates were observed when human primary CD4+ T cells and a human T-cell line were used as target cells. We also found equivalent recombination rates in the presence and absence of accessory genes vif, vpr, vpu, and nef. These results illustrate the power of recombination in generating viral population variation and predict the rapid assortment of mutations in the HIV-1 genome in infected individuals.

scholarly journals Structural Requirements for Recognition of the Human Immunodeficiency Virus Type 1 Core during Host Restriction in Owl Monkey Cells

2005 ◽  
Vol 79 (2) ◽  
pp. 869-875 ◽  
Author(s):  
Brett M. Forshey ◽  
Jiong Shi ◽  
Christopher Aiken
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Target Cells ◽  
Host Restriction ◽  
Amino Terminal ◽  
Immunodeficiency Virus ◽  
Owl Monkey ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection of simian cells is restricted at an early postentry step by host factors whose mechanism of action is unclear. These factors target the viral capsid protein (CA) and attenuate reverse transcription, suggesting that they bind to the HIV-1 core and interfere with its uncoating. To identify the relevant binding determinants in the capsid, we tested the capacity of viruses containing Gag cleavage site mutations and amino acid substitutions in CA to inhibit restriction of a wild type HIV-1 reporter virus in owl monkey cells. The results demonstrated that a stable, polymeric capsid and a correctly folded amino-terminal CA subunit interface are essential for saturation of host restriction in target cells by HIV-1 cores. We conclude that the owl monkey cellular restriction machinery recognizes a polymeric array of CA molecules, most likely via direct engagement of the HIV-1 capsid in target cells prior to uncoating.

scholarly journals Inhibitory Effect of Individual or Combinations of Broadly Neutralizing Antibodies and Antiviral Reagents against Cell-Free and Cell-to-Cell HIV-1 Transmission

2015 ◽  
Vol 89 (15) ◽  
pp. 7813-7828 ◽  
Author(s):  
Randi B. Gombos ◽  
Dror Kolodkin-Gal ◽  
Leila Eslamizar ◽  
Joshua O. Owuor ◽  
Emanuele Mazzola ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Neutralizing Antibodies ◽  
Virus Transmission ◽  
Target Cells ◽  
Broadly Neutralizing Antibodies ◽  
Free Virus ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACTTo date, most therapeutic and vaccine candidates for human immunodeficiency virus type 1 (HIV-1) are evaluated preclinically for efficacy against cell-free viral challenges. However, cell-associated HIV-1 is suggested to be a major contributor to sexual transmission by mucosal routes. To determine if neutralizing antibodies or inhibitors block cell-free and cell-associated virus transmission of diverse HIV-1 strains with different efficiencies, we tested 12 different antibodies and five inhibitors against four green fluorescent protein (GFP)-labeled HIV-1 envelope (Env) variants from transmitted/founder (T/F) or chronic infection isolates. We evaluated antibody/inhibitor-mediated virus neutralization using either TZM-bl target cells, in which infectivity was determined by virus-driven luciferase expression, or A3R5 lymphoblastoid target cells, in which infectivity was evaluated by GFP expression. In both the TZM-bl and A3R5 assays, cell-free virus or infected CD4+lymphocytes were used as targets for neutralization. We further hypothesized that the combined use of specific neutralizing antibodies targeting HIV-1 Env would more effectively prevent cell-associated virus transmission than the use of individual antibodies. The tested antibody combinations included two gp120-directed antibodies, VRC01 and PG9, or VRC01 with the gp41-directed antibody 10E8. Our results demonstrated that cell-associated virus was less sensitive to neutralizing antibodies and inhibitors, particularly using the A3R5 neutralization assay, and the potencies of these neutralizing agents differed among Env variants. A combination of different neutralizing antibodies that target specific sites on gp120 led to a significant reduction in cell-associated virus transmission. These assays will help identify ideal combinations of broadly neutralizing antibodies to use for passive preventive antibody administration and further characterize targets for the most effective neutralizing antibodies/inhibitors.IMPORTANCEPrevention of the transmission of human immunodeficiency virus type 1 (HIV-1) remains a prominent goal of HIV research. The relative contribution of HIV-1 within an infected cell versus cell-free HIV-1 to virus transmission remains debated. It has been suggested that cell-associated virus is more efficient at transmitting HIV-1 and more difficult to neutralize than cell-free virus. Several broadly neutralizing antibodies and retroviral inhibitors are currently being studied as potential therapies against HIV-1 transmission. The present study demonstrates a decrease in neutralizing antibody and inhibitor efficiencies against cell-associated compared to cell-free HIV-1 transmission among different strains of HIV-1. We also observed a significant reduction in virus transmission using a combination of two different neutralizing antibodies that target specific sites on the outermost region of HIV-1, the virus envelope. Therefore, our findings support the use of antibody combinations against both cell-free and cell-associated virus in future candidate therapy regimens.

scholarly journals How Many Human Immunodeficiency Virus Type 1-Infected Target Cells Can a Cytotoxic T-Lymphocyte Kill?

2005 ◽  
Vol 79 (21) ◽  
pp. 13579-13586 ◽  
Author(s):  
W. David Wick ◽  
Otto O. Yang ◽  
Lawrence Corey ◽  
Steven G. Self
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Target Cells ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Hiv 1

ABSTRACT The antiviral role of CD8+ cytotoxic T lymphocytes (CTLs) in human immunodeficiency virus type 1 (HIV-1) infection is poorly understood. Specifically, the degree to which CTLs reduce viral replication by killing HIV-1-infected cells in vivo is not known. Here we employ mathematical models of the infection process and CTL action to estimate the rate that CTLs can kill HIV-1-infected cells from in vitro and in vivo data. Our estimates, which are surprisingly consistent considering the disparities between the two experimental systems, demonstrate that on average CTLs can kill from 0.7 to 3 infected target cells per day, with the variability in this figure due to epitope specificity or other factors. These results are compatible with the observed decline in viremia after primary infection being primarily a consequence of CTL activity and have interesting implications for vaccine design.

scholarly journals Infection with Vpr-Positive Human Immunodeficiency Virus Type 1 Impairs NK Cell Function Indirectly through Cytokine Dysregulation of Infected Target Cells

2008 ◽  
Vol 82 (14) ◽  
pp. 7189-7200 ◽  
Author(s):  
Biswanath Majumder ◽  
Narasimhan J. Venkatachari ◽  
Shaylee O'Leary ◽  
Velpandi Ayyavoo
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cell Function ◽  
Nk Cell ◽  
Target Cells ◽  
Immunodeficiency Virus ◽  
Ifn Γ ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection has been implicated in impairing various aspects of NK cell function in viremic condition, and several viral factors contribute to these defects. Here, we evaluated the effect of HIV-1 Vpr on NK cell cytolytic function and cytokine (gamma interferon [IFN-γ]) production in the context of infection and exposure. Our data indicate that NK cells derived from a peripheral blood mononuclear cell culture infected in vitro with HIV-1 vpr(+) virus or exposed to recombinant Vpr protein exhibited reduced target cell killing in conjunction with diminished expression of CD107a and reduced IFN-γ production compared to their Vpr-negative counterparts. This Vpr-induced NK cell defect is in part through differential regulation of interleukin-12 and transforming growth factor β production by the infected target cells and concomitant activation of Smad3 signaling pathway. Collectively, these results illustrate the ability of Vpr to impair NK cell-mediated innate immune functions indirectly by dysregulating multiple cytokines in the infected target cells, thus increasing disease severity and affecting the final outcome in HIV-1 infection.

scholarly journals Human Seminal Plasma Abrogates the Capture and Transmission of Human Immunodeficiency Virus Type 1 to CD4+ T Cells Mediated by DC-SIGN

2007 ◽  
Vol 81 (24) ◽  
pp. 13723-13734 ◽  
Author(s):  
Juan Sabatté ◽  
Ana Ceballos ◽  
Silvina Raiden ◽  
Mónica Vermeulen ◽  
Karen Nahmod ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Seminal Plasma ◽  
Intercellular Adhesion Molecule ◽  
Target Cells ◽  
Human Seminal Plasma ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN) is expressed by dendritic cells (DCs) at mucosal surfaces and appears to play an important role in the dissemination of human immunodeficiency virus type 1 (HIV-1) infection. DC-SIGN binds HIV-1 gp120 and efficiently transmits the virus to T CD4+ cells, which become the center of viral replication. Semen represents the main vector for HIV-1 dissemination worldwide. In the present study we show that human seminal plasma (SP), even when used at very high dilutions (1:104 to 1:105), markedly inhibits the capture and transmission of HIV-1 to T CD4+ cells mediated by both DCs and B-THP-1-DC-SIGN cells. In contrast, SP does not inhibit the capture of HIV-1 by DC-SIGN-negative target cells, such as the T-cell line SupT-1, monocytes, and activated peripheral blood mononuclear cells. The SP inhibitor has a high molecular mass (>100 kDa) and directly interacts with DC-SIGN-positive target cells but not with HIV-1. Moreover, the inhibitor binds to concanavalin A, suggesting that it contains high-mannose N-linked carbohydrates. Of note, using biotin-labeled SP we found that the binding of SP components to DCs was abrogated by mannan, while their interaction with B-THP-1 cells was almost completely dependent on the expression of DC-SIGN. Since epithelium integrity is often compromised after vaginal or anal intercourse, as well as in the presence of ulcerative-sexually transmitted diseases, our results support the notion that components of the SP might be able to access to the subepithelium, inhibiting the recognition of HIV-1 gp120 by DC-SIGN-positive DCs.

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