In Vitro Phenotypic Susceptibility of Human Immunodeficiency Virus Type 2 Clinical Isolates to Protease Inhibitors

Desbois, Delphine; Roquebert, Bénédicte; Peytavin, Gilles; Damond, Florence; Collin, Gilles; Bénard, Antoine; Campa, Pauline; Matheron, Sophie; Chêne, Geneviève; Brun‐Vézinet, Françoise; Descamps, Diane; Cohort, French Anrs Hiv

doi:10.1128/aac.01284-07

Cited by 112 publications

(91 citation statements)

References 14 publications

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“…There are currently some phenotypic studies that allow the selection of better first-line therapies than those used a few years ago (16,61), but the knowledge of HIV-2 resistance pathways is still incomplete. Longitudinal data of an individual HIV-2 ϩ patient, in whom the initial ART regimen was associated with the rapid emergence of mutations and virological failure, illustrated that switching to another ART combination was associated with viremia suppression and a decline of cell-associated viral burden (Fig.…”

Section: Relationship Of Plasma and Cell-associated Viral Load With Cmentioning

confidence: 99%

Cell-Associated Viral Burden Provides Evidence of Ongoing Viral Replication in Aviremic HIV-2-Infected Patients

Soares¹,

Tendeiro

Foxall

et al. 2011

J Virol

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Viremia is significantly lower in HIV-2 than in HIV-1 infection, irrespective of disease stage. Nevertheless, the comparable proviral DNA burdens observed for these two infections indicate similar numbers of infected cells. Here we investigated this apparent paradox by assessing cell-associated viral replication. We found that untreated HIV-1-positive (HIV-1 ؉ ) and HIV-2 ؉ individuals, matched for CD4 T cell depletion, exhibited similar gag mRNA levels, indicating that significant viral transcription is occurring in untreated HIV-2 ؉ patients, despite the reduced viremia (undetectable to 2.6 ؋ 10 4 RNA copies/ml). However, tat mRNA transcripts were observed at significantly lower levels in HIV-2 ؉ patients, suggesting that the rate of de novo infection is decreased in these patients. Our data also reveal a direct relationship of gag and tat transcripts with CD4 and CD8 T cell activation, respectively. Antiretroviral therapy (ART)-treated HIV-2 ؉ patients showed persistent viral replication, irrespective of plasma viremia, possibly contributing to the emergence of drug resistance mutations, persistent hyperimmune activation, and poor CD4 T cell recovery that we observed with these individuals. In conclusion, we provide here evidence of significant ongoing viral replication in HIV-2 ؉ patients, further emphasizing the dichotomy between amount of plasma virus and cell-associated viral burden and stressing the need for antiretroviral trials and the definition of therapeutic guidelines for HIV-2 infection.

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Section: Relationship Of Plasma and Cell-associated Viral Load With Cmentioning

confidence: 99%

Cell-Associated Viral Burden Provides Evidence of Ongoing Viral Replication in Aviremic HIV-2-Infected Patients

Soares¹,

Tendeiro

Foxall

et al. 2011

J Virol

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“…The inhibitors APV, DRV and SQV were selected due to their distinct effects on the two types of virus. HIV-2 strains were shown to be susceptible to DRV 19 and to SQV, 20,21 while natural resistance to APV was found for several HIV-2 strains. [20][21][22] Thus, crystallographic and kinetic analysis of PR 1M , PR 1 and PR 2 will improve our understanding of the differences in inhibitor potency.…”

Section: Introductionmentioning

confidence: 99%

Critical differences in HIV‐1 and HIV‐2 protease specificity for clinical inhibitors

Tie¹,

Wang²,

Boross³

et al. 2012

Protein Science

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Clinical inhibitor amprenavir (APV) is less effective on HIV-2 protease (PR 2 ) than on HIV-1 protease (PR 1 ). We solved the crystal structure of PR 2 with APV at 1.5 Å resolution to identify structural changes associated with the lowered inhibition. Furthermore, we analyzed the PR 1 mutant (PR 1M ) with substitutions V32I, I47V, and V82I that mimic the inhibitor binding site of PR 2 . PR 1M more closely resembled PR 2 than PR 1 in catalytic efficiency on four substrate peptides and inhibition by APV, whereas few differences were seen for two other substrates and inhibition by saquinavir (SQV) and darunavir (DRV). High resolution crystal structures of PR 1M with APV, DRV, and SQV were compared with available PR 1 and PR 2 complexes. Val/Ile32 and Ile/Val47 showed compensating interactions with SQV in PR 1M and PR 1 , however, Ile82 interacted with a second SQV bound in an extension of the active site cavity of PR 1M . Residues 32 and 82 maintained similar interactions with DRV and APV in all the enzymes, whereas Val47 and Ile47 had opposing effects in the two subunits. Significantly diminished interactions were seen for the aniline of APV bound in PR 1M and PR 2 relative to the strong hydrogen bonds observed in PR 1 , consistent with 15-and 19-fold weaker inhibition, respectively. Overall, PR 1M partially replicates the specificity of PR 2 and gives insight into drug resistant mutations at residues 32, 47, and 82. Moreover, this analysis provides a structural explanation for the weaker antiviral effects of APV on HIV-2.

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“…We and others have previously shown that wild-type HIV-2 is at least partially resistant, in vitro, to the majority of PI FDA approved for the treatment of HIV-1, retaining clinically useful susceptibility only to SQV, LPV, and DRV (13)(14)(15)(16)(17)(18)(19)(20). Although it has long been known that the active centers of HIV-1 and HIV-2 proteases differ by only four amino acids (23), this observation has never been fully investigated.…”

Section: Discussionmentioning

confidence: 99%

“…HIV-2 is at least partially resistant to the majority of the HIV-1 PI approved by the U.S. Food and Drug Administration (FDA); only lopinavir (LPV), darunavir (DRV), and saquinavir (SQV) are active at clinically useful concentrations (13)(14)(15)(16)(17)(18)(19)(20). The determinants of intrinsic PI resistance in HIV-2 are unknown, but previous studies have identified just four residues in the protease binding cleft, at amino acid positions 32, 47, 76, and 82, that differ between HIV-1 and HIV-2 (6,(21)(22)(23)(24)(25).…”

mentioning

confidence: 99%

Four Amino Acid Changes in HIV-2 Protease Confer Class-Wide Sensitivity to Protease Inhibitors

Raugi

Smith

Gottlieb

2016

J Virol

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Protease is essential for retroviral replication, and protease inhibitors (PI) are important for treating HIV infection. HIV-2 exhibits intrinsic resistance to most FDA-approved HIV-1 PI, retaining clinically useful susceptibility only to lopinavir, darunavir, and saquinavir. The mechanisms for this resistance are unclear; although HIV-1 and HIV-2 proteases share just 38 to 49% sequence identity, all critical structural features of proteases are conserved. Structural studies have implicated four amino acids in the ligand-binding pocket (positions 32, 47, 76, and 82). We constructed HIV-2 ROD9 molecular clones encoding the corresponding wild-type HIV-1 amino acids (I32V, V47I, M76L, and I82V) either individually or together (clone PR⌬4) and compared the phenotypic sensitivities (50% effective concentration [EC 50 ]) of mutant and wild-type viruses to nine FDA-approved PI. Single amino acid replacements I32V, V47I, and M76L increased the susceptibility of HIV-2 to multiple PI, but no single change conferred class-wide sensitivity. In contrast, clone PR⌬4 showed PI susceptibility equivalent to or greater than that of HIV-1 for all PI. We also compared crystallographic structures of wild-type HIV-1 and HIV-2 proteases complexed with amprenavir and darunavir to models of the PR⌬4 enzyme. These models suggest that the amprenavir sensitivity of PR⌬4 is attributable to stabilizing enzyme-inhibitor interactions in the P2 and P2= pockets of the protease dimer. Together, our results show that the combination of four amino acid changes in HIV-2 protease confer a pattern of PI susceptibility comparable to that of HIV-1, providing a structural rationale for intrinsic HIV-2 PI resistance and resolving long-standing questions regarding the determinants of differential PI susceptibility in HIV-1 and HIV-2. IMPORTANCEProteases are essential for retroviral replication, and HIV-1 and HIV-2 proteases share a great deal of structural similarity. However, only three of nine FDA-approved HIV-1 protease inhibitors (PI) are active against HIV-2. The underlying reasons for intrinsic PI resistance in HIV-2 are not known. We examined the contributions of four amino acids in the ligand-binding pocket of the enzyme that differ between HIV-1 and HIV-2 by constructing HIV-2 clones encoding the corresponding HIV-1 amino acids and testing the PI susceptibilities of the resulting viruses. We found that the HIV-2 clone containing all four changes (PR⌬4) was as susceptible as HIV-1 to all nine PI. We also modeled the PR⌬4 enzyme structure and compared it to existing crystallographic structures of HIV-1 and HIV-2 proteases complexed with amprenavir and darunavir. Our findings demonstrate that four positions in the ligand-binding cleft of protease are the primary cause of HIV-2 PI resistance.

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In Vitro Phenotypic Susceptibility of Human Immunodeficiency Virus Type 2 Clinical Isolates to Protease Inhibitors

Cited by 112 publications

References 14 publications

Cell-Associated Viral Burden Provides Evidence of Ongoing Viral Replication in Aviremic HIV-2-Infected Patients

Cell-Associated Viral Burden Provides Evidence of Ongoing Viral Replication in Aviremic HIV-2-Infected Patients

Critical differences in HIV‐1 and HIV‐2 protease specificity for clinical inhibitors

Four Amino Acid Changes in HIV-2 Protease Confer Class-Wide Sensitivity to Protease Inhibitors

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