scholarly journals Analysis of Human Immunodeficiency Virus Cytopathicity by Using a New Method for Quantitating Viral Dynamics in Cell Culture

2005 ◽  
Vol 79 (7) ◽  
pp. 4025-4032 ◽  
Author(s):  
Christina Speirs ◽  
Erik van Nimwegen ◽  
Diane Bolton ◽  
Mihaela Zavolan ◽  
Melody Duvall ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Human Immunodeficiency Virus ◽  
Cell Death ◽  
Death Rate ◽  
Time Dependent ◽  
Target Cells ◽  
Viral Dynamics ◽  
Death Rates ◽  
Immunodeficiency Virus ◽  
Infected Cells

ABSTRACT Human immunodeficiency virus (HIV) causes complex metabolic changes in infected CD4+ T cells that lead to cell cycle arrest and cell death by necrosis. To study the viral functions responsible for deleterious effects on the host cell, we quantitated the course of HIV type 1 infection in tissue cultures by using flow cytometry for a virally encoded marker protein, heat-stable antigen (HSA). We found that HSA appeared on the surface of the target cells in two phases: passive acquisition due to association and fusion of virions with target cells, followed by active protein expression from transcription of the integrated provirus. The latter event was necessary for decreased target cell viability. We developed a general mathematical model of viral dynamics in vitro in terms of three effective time-dependent rates: those of cell proliferation, infection, and death. Using this model we show that the predominant contribution to the depletion of viable target cells results from direct cell death rather than cell cycle blockade. This allows us to derive accurate bounds on the time-dependent death rates of infected cells. We infer that the death rate of HIV-infected cells is 80 times greater than that of uninfected cells and that the elimination of the vpr protein reduces the death rate by half. Our approach provides a general method for estimating time-dependent death rates that can be applied to study the dynamics of other viruses.

scholarly journals Expression of Nef Downregulates CXCR4, the Major Coreceptor of Human Immunodeficiency Virus, from the Surfaces of Target Cells and Thereby Enhances Resistance to Superinfection

2006 ◽  
Vol 80 (22) ◽  
pp. 11141-11152 ◽  
Author(s):  
Stephanie Venzke ◽  
Nico Michel ◽  
Ina Allespach ◽  
Oliver T. Fackler ◽  
Oliver T. Keppler
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Lymphocytes ◽  
Maximum Level ◽  
Target Cells ◽  
Class I Mhc ◽  
Mhc I ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Stromal Cell Derived Factor ◽  
Hiv 1

ABSTRACT Lentiviral Nef proteins are key factors for pathogenesis and are known to downregulate functionally important molecules, including CD4 and major histocompatibility complex class I (MHC-I), from the surfaces of infected cells. Recently, we demonstrated that Nef reduces cell surface levels of the human immunodeficiency virus type 1 (HIV-1) entry coreceptor CCR5 (N. Michel, I. Allespach, S. Venzke, O. T. Fackler, and O. T. Keppler, Curr. Biol. 15:714-723, 2005). Here, we report that Nef downregulates the second major HIV-1 coreceptor, CXCR4, from the surfaces of HIV-infected primary CD4 T lymphocytes with efficiencies comparable to those of the natural CXCR4 ligand, stromal cell-derived factor-1 alpha. Analysis of a panel of mutants of HIV-1SF2 Nef revealed that the viral protein utilized the same signature motifs for downmodulation of CXCR4 and MHC-I, including the proline-rich motif P73P76P79P82 and the acidic cluster motif E66E67E68E69. Expression of wild-type Nef, but not of specific Nef mutants, resulted in a perinuclear accumulation of the coreceptor. Remarkably, the carboxy terminus of CXCR4, which harbors the classical motifs critical for basal and ligand-induced receptor endocytosis, was dispensable for the Nef-mediated reduction of surface exposure. Functionally, the ability of Nef to simultaneously downmodulate CXCR4 and CD4 correlated with maximum-level protection of Nef-expressing target cells from fusion with cells exposing X4 HIV-1 envelopes. Furthermore, the Nef-mediated downregulation of CXCR4 alone on target T lymphocytes was sufficient to diminish cells' susceptibility to X4 HIV-1 virions at the entry step. The downregulation of chemokine coreceptors is a conserved activity of Nef to modulate infected cells, an important functional consequence of which is an enhanced resistance to HIV superinfection.

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 Human Immunodeficiency Virus Type 1 Vpr Protein Does Not Modulate Surface Expression of the CD4 Receptor

2002 ◽  
Vol 76 (8) ◽  
pp. 4125-4130 ◽  
Author(s):  
Enrique Argañaraz ◽  
María José Cortés ◽  
Sydney Leibel ◽  
Juan Lama
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Cell Surface ◽  
Target Cells ◽  
Viral Receptor ◽  
Cd4 Receptor ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Hiv 1

ABSTRACT The CD4 receptor is required for the entry of human immunodeficiency virus (HIV) into target cells. It has long been known that Nef, Env, and Vpu participate in the removal of the viral receptor from the cell surface. Recently, it has been proposed that the HIV type 1 (HIV-1) Vpr protein may also play a role in the downmodulation of CD4 from the surfaces of infected cells (L. Conti, B. Varano, M. C. Gauzzi, P. Matarrese, M. Federico, W. Malorani, F. Belardelli, and S. Gessani, J. Virol. 74:10207-10211, 2000). To investigate the possible role of Vpr in the downregulation of the viral receptor Vpr alleles from HIV-1 and simian immunodeficiency virus were transiently expressed in transformed T cells and in 293T fibroblasts, and their ability to modulate surface CD4 was evaluated. All Vpr alleles efficiently arrested cells in the G2 stage of the cell cycle. However, none of the tested Vpr proteins altered the expression of CD4 on the cell surface. In comparison, HIV-1 Nef efficiently downmodulated surface CD4 in all the experimental settings. Transformed T cells and primary lymphocytes were challenged with wild-type, Nef-defective, and Vpr-defective viruses. A significant reduction in the HIV-induced downmodulation of surface CD4 was observed in viruses lacking Nef. However, Vpr-deletion-containing viruses showed no defect in their ability to remove CD4 from the surfaces of infected cells. Our results indicate that Vpr does not play a role in the HIV-induced downmodulation of the CD4 receptor.

scholarly journals Targeting of human immunodeficiency virus-infected cells by CD8+ T lymphocytes armed with universal T-cell receptors

Blood ◽  
1994 ◽  
Vol 84 (9) ◽  
pp. 2878-2889 ◽  
Author(s):  
MR Roberts ◽  
L Qin ◽  
D Zhang ◽  
DH Smith ◽  
AC Tran ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
T Cell Receptors ◽  
Target Cells ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Retroviral Transduction ◽  
Cell Receptors ◽  
Immunodeficiency Virus ◽  
Infected Cells

We have developed an immunotherapeutic approach with potential application in the treatment of viral and malignant disease. We show that primary CD8+ T cells isolated from peripheral blood can be genetically modified by retroviral transduction to express high levels of universal (major histocompatibility complex-unrestricted) chimeric T- cell receptors specific for human immunodeficiency virus (HIV) antigens. Two classes of HIV-specific URs in which the antigen-binding domain is comprised of either CD4 or a single-chain antibody are capable of activating a number of T-cell effector functions in response to target cells, including cytolysis, in a highly sensitive and specific manner. Importantly, we have addressed a number of issues which, although particularly relevant to the clinical application of this approach in the treatment of HIV infection, may also impact on the potential of UR immunotherapy for other disease targets. The UR immunotherapeutic system is particularly suited for evaluation in the clinical setting.

scholarly journals SMAC Mimetic Plus Triple-Combination Bispecific HIVxCD3 Retargeting Molecules in SHIV.C.CH505-Infected, Antiretroviral Therapy-Suppressed Rhesus Macaques

2020 ◽  
Vol 94 (21) ◽  
Author(s):  
Amir Dashti ◽  
Chevaughn Waller ◽  
Maud Mavigner ◽  
Nils Schoof ◽  
Katharine J. Bar ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Antiretroviral Therapy ◽  
Rhesus Macaques ◽  
Viral Reservoir ◽  
Target Cells ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
The Impact ◽  
Hiv 1

ABSTRACT The “shock-and-kill” human immunodeficiency virus type 1 (HIV-1) cure strategy involves latency reversal followed by immune-mediated clearance of infected cells. We have previously shown that activation of the noncanonical NF-κB pathway using an inhibitor of apoptosis (IAP), AZD5582, reverses HIV/simian immunodeficiency virus (SIV) latency. Here, we combined AZD5582 with bispecific HIVxCD3 DART molecules to determine the impact of this approach on persistence. Rhesus macaques (RMs) (n = 13) were infected with simian/human immunodeficiency virus SHIV.C.CH505.375H.dCT, and triple antiretroviral therapy (ART) was initiated after 16 weeks. After 42 weeks of ART, 8 RMs received a cocktail of 3 HIVxCD3 DART molecules having human A32, 7B2, or PGT145 anti-HIV-1 envelope (Env) specificities paired with a human anti-CD3 specificity that is rhesus cross-reactive. The remaining 5 ART-suppressed RMs served as controls. For 10 weeks, a DART molecule cocktail was administered weekly (each molecule at 1 mg/kg of body weight), followed 2 days later by AZD5582 (0.1 mg/kg). DART molecule serum concentrations were well above those considered adequate for redirected killing activity against Env-expressing target cells but began to decline after 3 to 6 weekly doses, coincident with the development of antidrug antibodies (ADAs) against each of the DART molecules. The combination of AZD5582 and the DART molecule cocktail did not increase on-ART viremia or cell-associated SHIV RNA in CD4+ T cells and did not reduce the viral reservoir size in animals on ART. The lack of latency reversal in the model used in this study may be related to low pre-ART viral loads (median, <105 copies/ml) and low preintervention reservoir sizes (median, <102 SHIV DNA copies/million blood CD4+ T cells). Future studies to assess the efficacy of Env-targeting DART molecules or other clearance agents to reduce viral reservoirs after latency reversal may be more suited to models that better minimize immunogenicity and have a greater viral burden. IMPORTANCE The most significant barrier to an HIV-1 cure is the existence of the latently infected viral reservoir that gives rise to rebound viremia upon cessation of ART. Here, we tested a novel combination approach of latency reversal with AZD5582 and clearance with bispecific HIVxCD3 DART molecules in SHIV.C.CH505-infected, ART-suppressed rhesus macaques. We demonstrate that the DART molecules were not capable of clearing infected cells in vivo, attributed to the lack of quantifiable latency reversal in this model with low levels of persistent SHIV DNA prior to intervention as well as DART molecule immunogenicity.

scholarly journals FAT10: a Novel Mediator of Vpr-Induced Apoptosis in Human Immunodeficiency Virus-Associated Nephropathy

2009 ◽  
Vol 83 (22) ◽  
pp. 11983-11988 ◽  
Author(s):  
Alexandra Snyder ◽  
Zygimantas Alsauskas ◽  
Pengfei Gong ◽  
Paul E. Rosenstiel ◽  
Mary E. Klotman ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Human Immunodeficiency Virus ◽  
Cell Death ◽  
Epithelial Cells ◽  
Tubular Epithelial Cells ◽  
Renal Tubular Epithelial Cells ◽  
Tubular Cells ◽  
Immunodeficiency Virus ◽  
Renal Tubular ◽  
Induced Apoptosis

ABSTRACT Human immunodeficiency virus (HIV)-associated nephropathy is a significant cause of morbidity and mortality in HIV-infected persons. Vpr-induced cell cycle dysregulation and apoptosis of renal tubular epithelial cells are important components of the pathogenesis of HIV-associated nephropathy (HIVAN). FAT10 is a ubiquitin-like protein that is upregulated in renal tubular epithelial cells in HIVAN. In these studies, we report that Vpr induces increased expression of FAT10 in tubular cells and that inhibition of FAT10 expression prevents Vpr-induced apoptosis in human and murine tubular cells. Moreover, we found that Vpr interacts with FAT10 and that these proteins colocalize at mitochondria. These studies establish FAT10 as a novel mediator of Vpr-induced cell death.

scholarly journals The Vif accessory protein alters the cell cycle of human immunodeficiency virus type 1 infected cells

Virology ◽  
2007 ◽  
Vol 359 (2) ◽  
pp. 243-252 ◽  
Author(s):  
Jiangfang Wang ◽  
Jason M. Shackelford ◽  
Carolyn R. Casella ◽  
Debra K. Shivers ◽  
Eric L. Rapaport ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Accessory Protein ◽  
Immunodeficiency Virus ◽  
Infected Cells

scholarly journals Targeting of human immunodeficiency virus-infected cells by CD8+ T lymphocytes armed with universal T-cell receptors

Blood ◽  
1994 ◽  
Vol 84 (9) ◽  
pp. 2878-2889 ◽  
Author(s):  
MR Roberts ◽  
L Qin ◽  
D Zhang ◽  
DH Smith ◽  
AC Tran ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
T Cell Receptors ◽  
Target Cells ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Retroviral Transduction ◽  
Cell Receptors ◽  
Immunodeficiency Virus ◽  
Infected Cells

Abstract We have developed an immunotherapeutic approach with potential application in the treatment of viral and malignant disease. We show that primary CD8+ T cells isolated from peripheral blood can be genetically modified by retroviral transduction to express high levels of universal (major histocompatibility complex-unrestricted) chimeric T- cell receptors specific for human immunodeficiency virus (HIV) antigens. Two classes of HIV-specific URs in which the antigen-binding domain is comprised of either CD4 or a single-chain antibody are capable of activating a number of T-cell effector functions in response to target cells, including cytolysis, in a highly sensitive and specific manner. Importantly, we have addressed a number of issues which, although particularly relevant to the clinical application of this approach in the treatment of HIV infection, may also impact on the potential of UR immunotherapy for other disease targets. The UR immunotherapeutic system is particularly suited for evaluation in the clinical setting.

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