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De Luca A, Weidler J, Di Giambenedetto S, Coakley E, Cingolani A, Bates M, Lie Y, Pesano R, Cauda R, Schapiro J. Association of HIV-1 Replication Capacity With Treatment Outcomes in Patients With Virologic Treatment Failure. J Acquir Immune Defic Syndr 2007; 45:411-7. [PMID: 17554216 DOI: 10.1097/qai.0b013e318074f008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The extent to which HIV-1 replication capacity (RC) influences the response to therapy remains to be established. METHODS Phenotypic susceptibility and RC of baseline isolates (n = 139) from patients enrolled in the ARGENTA trial were measured and correlated to treatment outcomes over 36 months. RESULTS RC in baseline isolates correlated with the number of phenotypically active drugs (R = 0.34, P < 0.001). Crude viral RC did not predict treatment outcomes. When viral RC was adjusted by baseline CD4 cell counts, HIV-1 RNA levels, and phenotypic susceptibility to the rescue regimen, it showed significant association with the immunologic outcome (per log10 RC higher, mean difference in 36 months' time-averaged change from baseline CD4 count = -68 cells/microL; P = 0.020). In the subgroup of patients with 3 or more phenotypically active drugs in the salvage regimen (n = 35, median RC = 65%), subjects carrying isolates with RC < or =65% as compared to those with RC >65% had better time-averaged HIV-1 RNA responses (mean: -1.04 vs. -0.32 log10 copies/mL; P = 0.012) and CD4 cell responses (mean: 132 vs. -7 cells/microL; P = 0.006). Among patients with HIV-1 RNA levels persistently >500 copies/mL (n = 61), RC, on a log10 basis, was inversely associated with time-averaged 36-month CD4 cell responses (beta = -0.26; P = 0.046). CONCLUSION After normalizing for viral susceptibility to the employed regimen or in patient subsets with suboptimal virologic response, higher viral RC may predict worse subsequent treatment outcomes.
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Affiliation(s)
- Andrea De Luca
- Institute of Clinical Infectious Diseases, Policlinoco Universitario Agostino Gemelli, Catholic University of the Sacred Heart, Largo F. Vito 1, 00168 Rome, Italy.
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52
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Malet I, Wirden M, Derache A, Simon A, Katlama C, Calvez V, Marcelin AG. Primary genotypic resistance of HIV-1 to the maturation inhibitor PA-457 in protease inhibitor-experienced patients. AIDS 2007; 21:871-3. [PMID: 17415044 DOI: 10.1097/qad.0b013e3280b079d9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Sequences from 82 protease inhibitors (PI)-experienced patients were analysed for the presence of previously described in-vitro resistance mutations to PA-457 located in the C-terminal capside (H226Y, L231F, L231M) and in the N-terminal SP1 (A1V, A3T, A3V) within the CA-SP1 boundary domain. Overall, the CA-SP1 cleavage site was highly conserved in PI pre-treated patients and only one patient showed an L231M mutation. The impact of this mutation should be further addressed in vivo.
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Affiliation(s)
- Isabelle Malet
- Laboratoire de Virologie, Université Pierre et Marie Curie (Paris 6), France
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53
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Malet I, Roquebert B, Dalban C, Wirden M, Amellal B, Agher R, Simon A, Katlama C, Costagliola D, Calvez V, Marcelin AG. Association of Gag cleavage sites to protease mutations and to virological response in HIV-1 treated patients. J Infect 2007; 54:367-74. [DOI: 10.1016/j.jinf.2006.06.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Revised: 06/08/2006] [Accepted: 06/15/2006] [Indexed: 10/24/2022]
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Chiba-Mizutani T, Miura H, Matsuda M, Matsuda Z, Yokomaku Y, Miyauchi K, Nishizawa M, Yamamoto N, Sugiura W. Use of new T-cell-based cell lines expressing two luciferase reporters for accurately evaluating susceptibility to anti-human immunodeficiency virus type 1 drugs. J Clin Microbiol 2006; 45:477-87. [PMID: 17182760 PMCID: PMC1829063 DOI: 10.1128/jcm.01708-06] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Two new T-cell-based reporter cell lines were established to measure human immunodeficiency virus type 1 (HIV-1) infectivity. One cell line naturally expresses CD4 and CXCR4, making it susceptible to X4-tropic viruses, and the other cell line, in which a CCR5 expression vector was introduced, is susceptible to both X4- and R5-tropic viruses. Reporter cells were constructed by transfecting the human T-cell line HPB-Ma, which demonstrates high susceptibility to HIV-1, with genomes expressing two different luciferase reporters, HIV-1 long terminal repeat-driven firefly luciferase and cytomegalovirus promoter-driven renilla luciferase. Upon HIV infection, the cells expressed firefly luciferase at levels that were highly correlated (r2=0.91 to 0.98) with the production of the capsid antigen p24. The cells also constitutively expressed renilla luciferase, which was used to monitor cell numbers and viability. The reliability of the cell lines for two in vitro applications, drug resistance phenotyping and drug screening, was confirmed. As HIV-1 efficiently replicated in these cells, they could be used for multiple-round replication assays as an alternative method to a single-cycle replication protocol. Coefficients of variation for drug susceptibility evaluated with the cell lines ranged from 17 to 41%. The new cell lines were beneficial for evaluating antiretroviral drug resistance. Firefly luciferase gave a wider dynamic range for evaluating virus infectivity, and the introduction of renilla luciferase improved assay reproducibility. The cell lines were also beneficial for screening new antiretroviral agents, as false inhibition caused by the cytotoxicity of test compounds was easily detected by monitoring renilla luciferase activity.
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Affiliation(s)
- Tomoko Chiba-Mizutani
- AIDS Research Center, National Institute of Infectious Diseases, 4-7-1 Gakuenn, Musashimurayama, Tokyo 2080011, Japan
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55
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Verheyen J, Litau E, Sing T, Däumer M, Balduin M, Oette M, Fätkenheuer G, Rockstroh JK, Schuldenzucker U, Hoffmann D, Pfister H, Kaiser R. Compensatory Mutations at the HIV Cleavage Sites P7/P1 and P1/P6-Gag in Therapy-Naive and Therapy-Experienced Patients. Antivir Ther 2006. [DOI: 10.1177/135965350601100708] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background Mutations in the genome of HIV conferring drug resistance are a major reason for the failure of antiretroviral therapy, but they often compromise viral fitness. Protease (PR) cleavage site (CS) mutations could compensate for impaired replication capacity of drug-resistant viruses. Patients and methods We analysed the cleavage sites p1/p7 and p1/p6-gag of 500 HIV-1 subtype B infected patients. The collective consists of 275 therapy-naive and 225 therapy-experienced patients with at least one primary PR mutation, from whom eight underwent therapy-interruption in different clinical settings. Results Multiple mutations within the CS p7/p1 and p1/p6-gag accumulated in therapy-experienced isolates (p7/p1: A431V-K436R-I437V and p1/p6-gag: L449F/V-P452S-P453L/A). Further rare CS mutations were totally absent in therapy-naive viruses. Sixty percent of all therapy-experienced viruses exhibited at least one therapy-associated CS mutation, but so did 10% of therapy-naive viruses. The analysis of CS and PR mutations in therapy-experienced viruses revealed several positive correlations - A431V with L24I-M46I/L-I54V-V82A; I437V with I54V-V82F/T/S; L449V with I54M/L/S/T/A; and L449F/R452S/P453L: with D30N-I84V - whereas P453L and V82A were negatively correlated. Mutagenetic trees constructed form this cross-sectional data showed an ordered accumulation of the most prominent CS mutations along two pathways - L90M-I84V- P453L and I54-V82– A431V followed by either M46L or L24I. Furthermore, eight viruses with at least one therapy-associated mutation at each CS displayed an outstanding maintenance of major PR mutations during therapy interruption. Conclusions These findings emphasize the relevance of CS mutations in the evolution of HIV resistance to PR inhibitors. Therefore, therapy-associated CS mutations should be considered in HIV resistance tests to estimate viral fitness in different clinical settings.
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Affiliation(s)
- Jens Verheyen
- Institute of Virology, University of Cologne, Cologne, Germany
| | - Elena Litau
- Institute of Virology, University of Cologne, Cologne, Germany
| | - Tobias Sing
- Max Planck Institute for Informatics, Saarbrücken, Germany
| | - Martin Däumer
- Institute of Virology, University of Cologne, Cologne, Germany
| | - Melanie Balduin
- Institute of Virology, University of Cologne, Cologne, Germany
| | - Mark Oette
- Clinic for Gastroenterology, Hepatology and infectious Diseases, University Clinic Düsseldorf, Germany
| | - Gerd Fätkenheuer
- Department of Internal Medicine 1, University of Cologne, Cologne, Germany
| | | | | | - Daniel Hoffmann
- Center for Medical Biotechnology, University of Duisburg-Essen, Essen, Germany
| | - Herbert Pfister
- Institute of Virology, University of Cologne, Cologne, Germany
| | - Rolf Kaiser
- Institute of Virology, University of Cologne, Cologne, Germany
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van Maarseveen NM, de Jong D, Boucher CAB, Nijhuis M. An increase in viral replicative capacity drives the evolution of protease inhibitor-resistant human immunodeficiency virus type 1 in the absence of drugs. J Acquir Immune Defic Syndr 2006; 42:162-8. [PMID: 16645546 DOI: 10.1097/01.qai.0000219787.65915.56] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Little is known about the factors which drive the evolution of protease inhibitor-resistant human immunodeficiency virus type-1 in the absence of drugs. To examine if viral replicative capacity (RC) is an important determinant, we performed in vitro evolution experiments in the absence of drugs with a unique panel of 6 drug-resistant human immunodeficiency virus type-1 recombinant protease variants with a range of different RC. The experiments revealed that an increase in viral RC was indeed an important determinant of evolution. Initial protease inhibitor-resistant viruses with only a few protease mutations and a lowered RC evolved into viruses with an increased RC, either by reversion of primary resistance mutations or by the acquisition of compensatory mutations. For these viruses with a lowered RC, higher fitness peaks are most likely available in the sequence space. Evolution of these viruses in the absence of drugs will therefore drive them to new fitness peaks. In contrast, viruses with an RC comparable to wild type or even higher than wild type did not show any evolution. In the case of these viruses, it is not so likely that higher fitness peaks are present within the sequence space, and therefore, these variants will persist in the absence of drug pressure.
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Affiliation(s)
- Noortje M van Maarseveen
- Department of Virology, Eijkman-Winkler Center, University Medical Center Utrecht, Utrecht, The Netherlands
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57
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Boucher C, Larder B, Mellors J, Richman D. The Xivth International HIV Drug Resistance Workshop, Quebec City, Canada, June 2005. Antivir Ther 2006. [DOI: 10.1177/135965350601100516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This report summarizes research advances that further our understanding of the evolution, mechanisms and clinical impact of HIV drug resistance presented at the XIVth International HIV Drug Resistance Workshop held in Quebec City, Canada from June 7–11, 2005. The topics that were discussed included the clinical implications of resistance in mother-to-child transmission, breakthroughs in technologies for studying resistance, resistance to new antiretroviral agents, mechanisms of HIV drug resistance, epidemiological trends, and HIV fitness and pathogenesis.
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Yates PJ, Hazen R, St Clair M, Boone L, Tisdale M, Elston RC. In vitro development of resistance to human immunodeficiency virus protease inhibitor GW640385. Antimicrob Agents Chemother 2006; 50:1092-5. [PMID: 16495277 PMCID: PMC1426426 DOI: 10.1128/aac.50.3.1092-1095.2006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Development of in vitro resistance to GW640385, a new human immunodeficiency virus type 1 protease inhibitor, was studied. Variants characterized included one with <4-fold resistance and amino acid substitutions Q58E/A71V (protease) and P452K (Gag) and one with >50-fold resistance and amino acid substitutions L10F/G16E/E21K/A28S/M46I/F53L/A71V (protease) and L449F/P453T (Gag). The A28S substitution substantially reduced replication capacity.
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Affiliation(s)
- P J Yates
- UK Virology, GlaxoSmithKline Inc., Gunnels Wood Road, Stevenage SG1 2NY, United Kingdom.
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Quiñones-Mateu ME, Arts EJ. Virus fitness: concept, quantification, and application to HIV population dynamics. Curr Top Microbiol Immunol 2006; 299:83-140. [PMID: 16568897 DOI: 10.1007/3-540-26397-7_4] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Viral fitness has been broadly studied during the past three decades, mainly to test evolutionary models and population theories difficult to analyze and interpret with more complex organisms. More recent studies, however, are focused in the role of fitness on viral transmission, pathogenesis, and drug resistance. Here, we used human immunodeficiency virus (HIV) as one of the most relevant models to evaluate the importance of viral quasispecies and fitness in HIV evolution, population dynamics, disease progression, and potential clinical implications.
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Affiliation(s)
- M E Quiñones-Mateu
- Department of Molecular Genetics, Section Virology, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue/NN10, Cleveland, OH 44195, USA.
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Van Laethem K, Schrooten Y, Dedecker S, Van Heeswijck L, Deforche K, Van Wijngaerden E, Van Ranst M, Vandamme AM. A genotypic assay for the amplification and sequencing of gag and protease from diverse human immunodeficiency virus type 1 group M subtypes. J Virol Methods 2005; 132:181-6. [PMID: 16271771 DOI: 10.1016/j.jviromet.2005.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Revised: 09/13/2005] [Accepted: 10/03/2005] [Indexed: 10/25/2022]
Abstract
In human immunodeficiency virus type 1 (HIV-1), an interaction exists between the in vivo evolution of Gag protein and protease to escape from antiretroviral drug selective pressure. Therefore, it was decided to develop a genotypic assay for the amplification and sequencing of HIV-1 gag and protease. As the HIV-1 pandemic is characterised by a large genetic diversity, the assay developed was evaluated on a panel of 28 genetically divergent samples belonging to the following subtypes A1, B, C, D, F1, F2, G, H, J, CRF01-AE, CRF02-AG and CRF13-cpx. The assay displayed a detection limit ranging between 500 RNA copies/ml and 5000 RNA copies/ml plasma. Full-length sequences could be obtained for 25 samples. The population sequences of the three other samples lacked a part of the sequence because of heterogeneous signal, probably due to the presence of quasi-species with insertions/deletions of a different length.
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Affiliation(s)
- Kristel Van Laethem
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, Leuven, Belgium.
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61
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Holguín A, Alvarez A, Soriano V. Differences in the length of gag proteins among different HIV type 1 subtypes. AIDS Res Hum Retroviruses 2005; 21:886-93. [PMID: 16225417 DOI: 10.1089/aid.2005.21.886] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The effect of HIV-1 subtype on Gag protein length was examined in 122 individuals infected with different HIV-1 clades. Except for the P1 protein, a wide variation in the Gag proteins length was noticed. P2 was significantly shorter in 68 non-B with respect to 54 subtype B viruses. Nearly 85% of subtype B gag sequences harbored P2 with 14 or more amino acid (aa) residues, while 75% of non-B subtypes had P2 with 13 or less aa (p < 0.0001). The P7 protein was one residue shorter in 64.2% of non-B specimens but only in 9.3% of subtype B isolates (p = 0.0001). Overall, the P6gag protein length was modified by the presence of insertions, deletions, and stop codons in 89 (73%) of the tested population, but was mainly dependent of changes in non- B compared to B viruses (97% vs. 42.6%, p < 0.0001). However, insertions at P6(gag) (from 1 to 9 aa) were significantly more frequent in B than in non-B viruses (33.3% vs. 4.4%; p = 0.00002). Overall, conserved Gag residues and aa motifs, regardless of the genetic subtype, were 68.7% in P1, 54% in P7, 33.3% in P2, and 25% in P6(gag) proteins. In summary, length variation in Gag proteins is extensive across different HIV-1 subtypes, and could influence protein structure and function. The effect of Gag variation on the viral cycle among different HIV-1 clades needs to be further investigated.
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Affiliation(s)
- Africa Holguín
- Department of Infectious Diseases, Hospital Carlos III, 28029 Madrid, Spain.
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Abstract
The development of clinical symptoms, and clinical progression among persons infected with HIV-1 is the manifestation of the effects of the pathogenic viral life cycle of HIV-1. Individual variants of HIV-1 vary widely in features that determine viral fitness and virulence. HIV-1 exploits host antiviral responses, the APOBEC3G cytidine deaminase, and the low-fidelity HIV-1 reverse transcriptase, to ensure new variants with novel phenotypic features are continually present for expansion in response to changing conditions in the host, such as immune responses, or antiretroviral therapy. This high-level variance has led to a wide range in observed fitness and virulence, across strains of HIV-1. The HIV-1 pol replication capacity assay (pol RC) measures features of viral fitness, associates with elevated CD4+ T-cell counts, yet is not strongly associated with HIV-1 RNA levels. The biological basis for elevated CD4+ T-cell counts among those carrying a virus of low pol RC may be because of lowered virus infectivity, or restricted tissue replication.
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Affiliation(s)
- Jason D Barbour
- Gladstone Institute of Virology and Immunology, 1650 Owens Street, San Francisco, CA 94158, USA
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63
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Winters MA, Merigan TC. Insertions in the human immunodeficiency virus type 1 protease and reverse transcriptase genes: clinical impact and molecular mechanisms. Antimicrob Agents Chemother 2005; 49:2575-82. [PMID: 15980322 PMCID: PMC1168704 DOI: 10.1128/aac.49.7.2575-2582.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Mark A Winters
- Division of Infectious Diseases and Geographic Medicine, Stanford University, 300 Pasteur Drive, Room S-146, Stanford, California 94305-5107, USA.
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Prado JG, Parkin NT, Clotet B, Ruiz L, Martinez-Picado J. HIV type 1 fitness evolution in antiretroviral-experienced patients with sustained CD4+ T cell counts but persistent virologic failure. Clin Infect Dis 2005; 41:729-37. [PMID: 16080097 DOI: 10.1086/432619] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Accepted: 04/12/2005] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Over recent years, treatment guidelines for human immunodeficiency virus (HIV) infection have evolved from monotherapy to combination regimens that include > or = 3 active drugs, resulting in a sharp decrease in morbidity and mortality. In the present article, we evaluated changes in HIV type 1 viral fitness associated with the sequential introduction of antiretroviral treatment strategies in 4 chronically infected patients with sustained CD4 cell count despite having a persistently detectable viral load. METHODS Plasma samples were obtained before and during treatment to construct recombinant virus containing the 3'-end of gag, the protease and the reverse-transcriptase coding region. Drug susceptibility phenotype was evaluated with a panel of multiple reverse-transcriptase and protease inhibitors. Replicative capacity (RC) and infectivity were measured, and production of p24 was monitored after transfection. RESULTS Multidrug-resistant (MDR) viruses selected during long-term antiretroviral therapy were less fit and infectious than their wild-type or monotherapy-selected counterparts, with the exception of viruses recovered from patient B. In 3 of 4 cases, p24 kinetics after transfection showed a delay in viral production of recombinant viruses containing MDR mutations. Data from the RC and infectivity assays showed good correlation (P < .03) and corroborated the p24 kinetics data. CONCLUSIONS This study shows that accumulation of MDR mutations during long-term antiretroviral treatment results, albeit not in all cases, in reductions of viral fitness.
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Affiliation(s)
- Julia G Prado
- IrsiCaixa Foundation, Hospital Germans Trias i Pujol, Universitat Autonoma de Barcelona, Badalona, Spain
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Buckheit RW. Understanding HIV resistance, fitness, replication capacity and compensation: targeting viral fitness as a therapeutic strategy. Expert Opin Investig Drugs 2005; 13:933-58. [PMID: 15268633 DOI: 10.1517/13543784.13.8.933] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The increasingly prevalent emergence of drug-resistant virus strains in patients being treated with highly active antiretroviral regimens and the increasing rates of transmission of drug-resistant virus strains have focused attention on the critical need for additional antiretroviral agents with novel mechanisms of action and enhanced potency. Furthermore, novel means of employing highly active antiretroviral therapy are needed to reduce or eliminate the virological treatment failures that currently occur. Over the past several years, evidence has mounted supporting the fact that the emergence of resistant strains is associated with reductions in viral fitness, yielding decreases in plasma virus load in treated patients harbouring resistant populations of the virus. Additional mutations that serve to modify fitness (compensatory mutations) and mutations that impact the viral replication capacity also emerge under the selective pressure of drug treatment, and have both negative and positive effects on virus growth. Fitness is generally accepted to refer to the ability of HIV to replicate in a defined environment and thus is used to describe the viral replication potential in the absence of the drug. Although viral fitness and replication capacity are related in some ways, it is important to recognise that viral fitness is not the same as viral replication capacity. This review will assess the recent literature on antiviral drug resistance, viral fitness and viral replication capacity, and discuss means by which the adaptability of HIV to respond rapidly to antiviral treatment through mutation may be used against it. This would be done by treating patients with an aim to lock the deleterious mutations into the resistant virus genome, resulting in a positive therapeutic outcome despite the presence of resistance to the selecting agents. The review will specifically discuss the literature on nucleoside and non-nucleoside reverse transcriptase inhibitors, protease inhibitors, integrase inhibitors, fusion inhibitors, as well as other biological factors involved in viral fitness.
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Affiliation(s)
- Robert W Buckheit
- ImQuest BioSciences, Inc., 7340 Executive Way, Suite R, Frederick, Maryland 21704, USA.
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