scholarly journals Persistence of Wild-Type Virus and Lack of Temporal Structure in the Latent Reservoir for Human Immunodeficiency Virus Type 1 in Pediatric Patients with Extensive Antiretroviral Exposure

2002 ◽  
Vol 76 (18) ◽  
pp. 9481-9492 ◽  
Author(s):  
Christian T. Ruff ◽  
Stuart C. Ray ◽  
Patricia Kwon ◽  
Rebekah Zinn ◽  
Amanda Pendleton ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Temporal Structure ◽  
Latent Reservoir ◽  
Drug Resistant ◽  
Wild Type ◽  
Time Points ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Although highly active antiretroviral therapy (HAART) for human immunodeficiency virus type 1 (HIV-1) infection can reduce levels of HIV-1 RNA in plasma to below the limit of detection, replication-competent forms of the virus persist in all infected individuals. One form of persistence involves a stable reservoir of latent but potentially infectious virus that resides in resting memory CD4+ T cells. The mechanisms involved in maintaining this latent reservoir are incompletely understood. In the present study, we examined the dynamic characteristics of this reservoir in a cohort of children who developed drug-resistant HIV-1 as a result of extensive exposure to inadequately suppressive one- or two-drug regimens prior to the advent of HAART. We have previously shown that drug-resistant viruses selected by nonsuppressive pre-HAART regimens can enter and persist in this reservoir. We have extended these findings here by demonstrating that archival wild-type HIV-1 persists in this reservoir despite the fact that in these patients drug-resistant mutants have been favored by the selective conditions for many years. Phylogenetic analysis of replication-competent viruses persisting in resting CD4+ T cells revealed a striking lack of temporal structure in the sense that isolates obtained at later time points did not show greater sequence divergence than isolates from earlier time points. The persistence of drug-sensitive virus and the lack of temporal structure in the latent reservoir provide genetic evidence for the idea that HIV-1 can persist in a latent form free of selective pressure from antiretroviral drugs in long-lived resting memory CD4+ T cells. Although there may be other mechanisms for viral persistence, this stable pool of latently infected cells is of significant concern because of its potential to serve as a lasting source of replication-competent viruses, including the infecting wild-type form and all drug-resistant variants that have arisen subsequently.

scholarly journals A Novel Assay Allows Genotyping of the Latent Reservoir for Human Immunodeficiency Virus Type 1 in the Resting CD4+ T Cells of Viremic Patients

2005 ◽  
Vol 79 (8) ◽  
pp. 5185-5202 ◽  
Author(s):  
Daphne Monie ◽  
Rachel P. Simmons ◽  
Richard E. Nettles ◽  
Tara L. Kieffer ◽  
Yan Zhou ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Latent Reservoir ◽  
Drug Resistant ◽  
Plasma Virus ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT A latent reservoir for human immunodeficiency virus type 1 (HIV-1) consisting of integrated provirus in resting memory CD4+ T cells prevents viral eradication in patients on highly active antiretroviral therapy (HAART). It is difficult to analyze the nature and dynamics of this reservoir in untreated patients and in patients failing therapy, because it is obscured by an excess of unintegrated viral DNA that constitutes the majority of viral species in resting CD4+ T cells from viremic patients. Therefore, we developed a novel culture assay that stimulates virus production from latent, integrated HIV-1 in resting CD4+ T cells in the presence of antiretroviral drugs that prevent the replication of unintegrated virus. Following activation, resting CD4+ T cells with integrated HIV-1 DNA produced virus particles for several days, with peak production at day 5. Using this assay, HIV-1 pol sequences from the resting CD4+ T cells of viremic patients were found to be genetically distinct from contemporaneous plasma virus. Despite the predominance of a relatively homogeneous population of drug-resistant viruses in the plasma of patients failing HAART, resting CD4+ T cells harbored a diverse array of wild-type and archival drug-resistant viruses that were less fit than plasma virus in the context of current therapy. These results provide the first direct evidence that resting CD4+ T cells serve as a stable reservoir for HIV-1 even in the setting of high levels of viremia. The ability to analyze archival species in viremic patients may have clinical utility in detecting drug-resistant variants not present in the plasma.

scholarly journals High Potency of Indolyl Aryl Sulfone Nonnucleoside Inhibitors towards Drug-Resistant Human Immunodeficiency Virus Type 1 Reverse Transcriptase Mutants Is Due to Selective Targeting of Different Mechanistic Forms of the Enzyme

2005 ◽  
Vol 49 (11) ◽  
pp. 4546-4554 ◽  
Author(s):  
Reynel Cancio ◽  
Romano Silvestri ◽  
Rino Ragno ◽  
Marino Artico ◽  
Gabriella De Martino ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Mechanism Of Action ◽  
Drug Resistant ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Indolyl aryl sulfone (IAS) nonnucleoside inhibitors have been shown to potently inhibit the growth of wild-type and drug-resistant human immunodeficiency virus type 1 (HIV-1), but their exact mechanism of action has not been elucidated yet. Here, we describe the mechanism of inhibition of HIV-1 reverse transcriptase (RT) by selected IAS derivatives. Our results showed that, depending on the substitutions introduced in the IAS common pharmacophore, these compounds can be made selective for different enzyme-substrate complexes. Moreover, we showed that the molecular basis for this selectivity was a different association rate of the drug to a particular enzymatic form along the reaction pathway. By comparing the activities of the different compounds against wild-type RT and the nonnucleoside reverse transcriptase inhibitor-resistant mutant Lys103Asn, it was possible to hypothesize, on the basis of their mechanism of action, a rationale for the design of drugs which could overcome the steric barrier imposed by the Lys103Asn mutation.

scholarly journals Intracellular Substrates for the Primer-Unblocking Reaction by Human Immunodeficiency Virus Type 1 Reverse Transcriptase: Detection and Quantitation in Extracts from Quiescent- and Activated-Lymphocyte Subpopulations

2005 ◽  
Vol 49 (5) ◽  
pp. 1761-1769 ◽  
Author(s):  
Anthony J. Smith ◽  
Peter R. Meyer ◽  
Deshratn Asthana ◽  
Margarita R. Ashman ◽  
Walter A. Scott
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Wild Type ◽  
Cell Extracts ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Treatment of human immunodeficiency virus type 1 (HIV-1)-infected patients with 3′-azido-3′-deoxythymidine (AZT) selects for mutant forms of viral reverse transcriptase (RT) with increased ability to remove chain-terminating nucleotides from blocked DNA chains. We tested various cell extracts for the presence of endogenous acceptor substrates for this reaction. Cell extracts incubated with HIV-1 RT and [32P]ddAMP-terminated DNA primer/template gave rise to 32P-labeled adenosine 2′,3′-dideoxyadenosine 5′,5′′′−P1,P4-tetraphosphate (Ap4ddA), ddATP, Gp4ddA, and Ap3ddA, corresponding to the transfer of [32P]ddAMP to ATP, PPi, GTP, and ADP, respectively. Incubation with [32P]AZT monophosphate (AZTMP)-terminated primer/template gave rise to the analogous 32P-labeled AZT derivatives. Based on the rates of formation of the specific excision products, ATP and PPi levels were determined: ATP was present at 1.3 to 2.2 mM in H9 cells, macrophages, and unstimulated CD4+ or CD8+ T cells, while PPi was present at 7 to 15 μM. Under these conditions, the ATP-dependent reaction predominated, and excision by the AZT-resistant mutant RT was more efficient than wild type RT. Activated CD4+ or CD8+ T cells contained 1.4 to 2.7 mM ATP and 55 to 79 μM PPi. These cellular PPi concentrations are lower than previously reported; nonetheless, the PPi-dependent reaction predominated in extracts from activated T cells, and excision by mutant and wild-type RT occurred with similar efficiency. While PPi-dependent excision may contribute to AZT resistance in vivo, it is likely that selection of AZT-resistant mutants occurs primarily in an environment where the ATP-dependent reaction predominates.

scholarly journals Characterization of Chemokine Receptor Utilization of Viruses in the Latent Reservoir for Human Immunodeficiency Virus Type 1

2000 ◽  
Vol 74 (17) ◽  
pp. 7824-7833 ◽  
Author(s):  
Theodore Pierson ◽  
Trevor L. Hoffman ◽  
Joel Blankson ◽  
Diana Finzi ◽  
Karen Chadwick ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Chemokine Receptor ◽  
Latent Reservoir ◽  
Immunodeficiency Virus ◽  
Latently Infected ◽  
Hiv 1

ABSTRACT Latently infected resting CD4+ T cells provide a long-term reservoir for human immunodeficiency virus type 1 (HIV-1) and are likely to represent the major barrier to virus eradication in patients on combination antiretroviral therapy. The mechanisms by which viruses enter the latent reservoir and the nature of the chemokine receptors involved have not been determined. To evaluate the phenotype of the virus in this compartment with respect to chemokine receptor utilization, full-length HIV-1 env genes were cloned from latently infected cells and assayed functionally. We demonstrate that the majority of the viruses in the latent reservoir utilize CCR5 during entry, although utilization of several other receptors, including CXCR4, was observed. No alternative coreceptors were shown to be involved in a systematic fashion. Although R5 viruses are present in the latent reservoir, CCR5 was not expressed at high levels on resting CD4+ T cells. To understand the mechanism by which R5 viruses enter latent reservoir, the ability of an R5 virus, HIV-1 Ba-L, to infect highly purified resting CD4+ T lymphocytes from uninfected donors was evaluated. Entry of Ba-L could be observed when virus was applied at a multiplicity approaching 1. However, infection was limited to a subset of cells expressing low levels of CCR5 and markers of immunologic memory. Naive cells could not be infected by an R5 virus even when challenged with a large inoculum. Direct cell fractionation studies showed that latent virus is present predominantly in resting memory cells but also at lower levels in resting naive cells. Taken together, these findings provide support for the hypothesis that the direct infection of naive T cells is not the major mechanism by which the latent infection of resting T cells is established.

scholarly journals Individual Contributions of Mutant Protease and Reverse Transcriptase to Viral Infectivity, Replication, and Protein Maturation of Antiretroviral Drug-Resistant Human Immunodeficiency Virus Type 1

2001 ◽  
Vol 75 (7) ◽  
pp. 3291-3300 ◽  
Author(s):  
Gabriela Bleiber ◽  
Miguel Munoz ◽  
Angela Ciuffi ◽  
Pascal Meylan ◽  
Amalio Telenti
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Drug Resistant ◽  
Wild Type ◽  
Protein Maturation ◽  
Antiretroviral Drug ◽  
Immunodeficiency Virus ◽  
Individual Contributions ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) variants resistant to protease (PR) and reverse transcriptase (RT) inhibitors may display impaired infectivity and replication capacity. The individual contributions of mutated HIV-1 PR and RT to infectivity, replication, RT activity, and protein maturation (herein referred to as “fitness”) in recombinant viruses were investigated by separately cloning PR, RT, and PR-RT cassettes from drug-resistant mutant viral isolates into the wild-type NL4-3 background. Both mutant PR and RT contributed to measurable deficits in fitness of viral constructs. In peripheral blood mononuclear cells, replication rates (means ± standard deviations) of RT recombinants were 72.5% ± 27.3% and replication rates of PR recombinants were 60.5% ± 33.6% of the rates of NL4-3. PR mutant deficits were enhanced in CEM T cells, with relative replication rates of PR recombinants decreasing to 15.8% ± 23.5% of NL4-3 replication rates. Cloning of the cognate RT improved fitness of some PR mutant clones. For a multidrug-resistant virus transmitted through sexual contact, RT constructs displayed a marked infectivity and replication deficit and diminished packaging of Pol proteins (RT content in virions diminished by 56.3% ± 10.7%, and integrase content diminished by 23.3% ± 18.4%), a novel mechanism for a decreased-fitness phenotype. Despite the identified impairment of recombinant clones, fitness of two of the three drug-resistant isolates was comparable to that of wild-type, susceptible viruses, suggestive of extensive compensation by genomic regions away from PR and RT. Only limited reversion of mutated positions to wild-type amino acids was observed for the native isolates over 100 viral replication cycles in the absence of drug selective pressure. These data underscore the complex relationship between PR and RT adaptive changes and viral evolution in antiretroviral drug-resistant HIV-1.

scholarly journals Wild-Type Levels of Nuclear Localization and Human Immunodeficiency Virus Type 1 Replication in the Absence of the Central DNA Flap

2002 ◽  
Vol 76 (23) ◽  
pp. 12078-12086 ◽  
Author(s):  
Ana Limón ◽  
Noriko Nakajima ◽  
Richard Lu ◽  
Hina Z. Ghory ◽  
Alan Engelman
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
Human Immunodeficiency Virus Type ◽  
Nuclear Localization ◽  
Nuclear Import ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Numerous factors have been implicated in the nuclear localization of retroviral preintegration complexes. Whereas sequences in human immunodeficiency virus type 1 (HIV-1) matrix, Vpr, and integrase proteins were initially reported to function specifically in nondividing cells, other recently identified sequences apparently function in dividing cells as well. One of these, the central DNA flap formed during reverse transcription, is specific to lentiviruses. It was previously reported that flap-negative (F−) HIV-1LAI was completely defective for viral spread in the MT-4 T-cell line, yet F− HIV-1 vectors were only 2- to 10-fold defective in various single-round transduction assays. To address these different findings, we analyzed the infectivity and nuclear localization phenotypes of two highly related T-cell-tropic strains, HIV-1NL4-3 and a derivative of HIV-1HXBc2 deficient for both Vpr and Nef. In stark contrast to the previous report, F− derivatives of both strains replicated efficiently in MT-4 cells. F− HIV-1NL4-3 also spread like wild-type HIV-1NL4-3 in infected Jurkat and primary T-cell cultures. In contrast, F− HIV-1HXBc2 was replication defective in primary T cells. Results of real-time quantitative PCR assays, however, indicated that F− HIV-1HXBc2 entered primary T-cell nuclei as efficiently as its wild-type counterpart. Thus, the F− HIV-1HXBc2 growth defect did not appear to correlate with defective nuclear import. Consistent with this observation, wild-type nef restored replication to F− HIV-1HXBc2 in primary T cells. Our results indicate that the central DNA flap does not play a major role in either preintegration complex nuclear import or HIV-1 replication in a variety of cell types.

scholarly journals Competitive Fitness of Nevirapine-Resistant Human Immunodeficiency Virus Type 1 Mutants

2004 ◽  
Vol 78 (2) ◽  
pp. 603-611 ◽  
Author(s):  
Jennifer A. Collins ◽  
M. Gregory Thompson ◽  
Elijah Paintsil ◽  
Melisa Ricketts ◽  
Joanna Gedzior ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Drug Resistant ◽  
Wild Type ◽  
Competitive Fitness ◽  
Immunodeficiency Virus ◽  
Resistant Mutants ◽  
Nevirapine Resistance ◽  
Hiv 1

ABSTRACT Determining the fitness of drug-resistant human immunodeficiency virus type 1 (HIV-1) strains is necessary for the development of population-based studies of resistance patterns. For this purpose, we have developed a reproducible, systematic assay to determine the competitive fitness of HIV-1 drug-resistant mutants. To demonstrate the applicability of this assay, we tested the fitness of the five most common nevirapine-resistant mutants (103N, 106A, 181C, 188C, and 190A), with mutations in HIV-1 reverse transcriptase (RT), singly and in combination (for a total of 31 variants) in a defined HIV-1 background. For these experiments, the 27 RT variants that produced viable virus were cocultured with wild-type virus without nevirapine. The ratios of the viral species were determined over time by utilization of a quantitative real-time RT-PCR-based assay. These experiments revealed that all of the viable variants were less fit than the wild type and demonstrated that the order of relative fitness of the single mutants tested was as follows: 103N > 181C > 190A > 188C > 106A. This order correlated with the commonality of these mutants as a result of nevirapine monotherapy. These investigations also revealed that, on average, the double mutants were less fit than the single mutants and the triple mutants were less fit than the double mutants. However, the fitness of the single and double mutants was often not predictive of the fitness of the derivative triple mutants, suggesting the presence of complex interactions between the closely aligned residues that confer nevirapine resistance. This complexity was also evident from the observation that all three of the replication-competent quadruple mutants were fitter than most of the triple mutants, and in some cases, even the double mutants. Our data suggest that, in many cases, viral fitness is the determining factor in the evolution of nevirapine-resistant mutants in vivo, that interactions between the residues that confer nevirapine resistance are complex, and that these interactions substantially affect reverse transcriptase structure and/or function.

scholarly journals Compartmentalization of Human Immunodeficiency Virus Type 1 between Blood Monocytes and CD4+ T Cells during Infection

2004 ◽  
Vol 78 (15) ◽  
pp. 7883-7893 ◽  
Author(s):  
Jennifer A. Fulcher ◽  
Yon Hwangbo ◽  
Rafael Zioni ◽  
David Nickle ◽  
Xudong Lin ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Time Points ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Distinct sequences of human immunodeficiency virus type 1 (HIV-1) have been found between different tissue compartments or subcompartments within a given tissue. Whether such compartmentalization of HIV-1 occurs between different cell populations is still unknown. Here we address this issue by comparing HIV-1 sequences in the second constant region through the fifth hypervariable region (C2 to V5) of the surface envelope glycoprotein (Env) between viruses in purified blood CD14+ monocytes and CD4+ T cells obtained longitudinally from five infected patients over a time period ranging from 117 to 3,409 days postseroconversion. Viral populations in both cell types at early infection time points appeared relatively homogeneous. However, later in infections, all five patients showed heterogeneous populations in both CD14+ monocytes and CD4+ T cells. Three of the five patients had CD14+ monocyte populations with significantly more genetic diversity than the CD4+ T-cell population, while the other two patients had more genetic diversity in CD4+ T cells. The cellular compartmentalization of HIV-1 between CD14+ monocytes and CD4+ T cells was not seen early during infections but was evident at the later time points for all five patients, indicating an association of viral compartmentalization with the time course of HIV-1 infection. The majority of HIV-1 V3 sequences indicated a macrophage-tropic phenotype, while a V3 sequence-predicted T-cell tropic virus was found in the CD4+ T cells and CD14+ monocytes of two patients. These findings suggest that HIV-1 in CD14+ monocytes could disseminate and evolve independently from that in CD4+ T cells over the course of HIV-1 infection, which may have implications on the development of new therapeutic strategies.

scholarly journals Hydroxyurea Enhances the Activities of Didanosine, 9-[2-(Phosphonylmethoxy)ethyl]adenine, and 9-[2-(Phosphonylmethoxy)propyl]adenine against Drug-Susceptible and Drug-Resistant Human Immunodeficiency Virus Isolates

1999 ◽  
Vol 43 (8) ◽  
pp. 2046-2050 ◽  
Author(s):  
Sarah Palmer ◽  
Robert W. Shafer ◽  
Thomas C. Merigan
Keyword(s):  
Human Immunodeficiency Virus ◽  
Drug Resistant ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Hiv Type 1 ◽  
Virus Isolates ◽  
Hiv 1

ABSTRACT We assessed the effects of hydroxyurea (HU) at a concentration of 50 μM on the in vitro activities of 2′,3′-dideoxyinosine (ddI), 9-[2-(phosphonylmethoxy)ethyl]adenine (PMEA), and 9-[2-(phosphonylmethoxy)propyl]adenine (PMPA) against a wild-type human immunodeficiency virus (HIV) type 1 (HIV-1) laboratory isolate and a panel of five well-characterized drug-resistant HIV isolates. Fifty micromolar HU significantly increased the activities of ddI, PMEA, and PMPA against both the wild-type and the drug-resistant HIV-1 isolates. In fixed combinations, both ddI and PMEA were synergistic with HU against wild-type and drug-resistant viruses.

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