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Van Rompay KKA. Evaluation of antiretrovirals in animal models of HIV infection. Antiviral Res 2009; 85:159-75. [PMID: 19622373 DOI: 10.1016/j.antiviral.2009.07.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 07/07/2009] [Accepted: 07/13/2009] [Indexed: 01/07/2023]
Abstract
Animal models of HIV infection have played an important role in the development of antiretroviral drugs. Although each animal model has its limitations and never completely mimics HIV infection of humans, a carefully designed study allows experimental approaches that are not feasible in humans, but that can help to better understand disease pathogenesis and to provide proof-of-concept of novel intervention strategies. While rodent and feline models are useful for initial screening, further testing is best done in non-human primate models, such as simian immunodeficiency virus (SIV) infection of macaques, because they share more similarities with HIV infection of humans. In the early years of the HIV pandemic, non-human primate models played a relatively minor role in the antiretroviral drug development process. Since then, a better understanding of the disease and the development of better drugs and assays to monitor antiviral efficacy have increased the usefulness of the animal models. In particular, non-human primate models have provided proof-of-concept for (i) the benefits of chemoprophylaxis and early treatment, (ii) the preclinical efficacy of novel drugs such as tenofovir, (iii) the virulence and clinical significance of drug-resistant viral mutants, and (iv) the role of antiviral immune responses during drug therapy. Ongoing comparison of results obtained in animal models with those observed in human studies will further validate and improve these animal models so they can continue to help advance our scientific knowledge and to guide clinical trials. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol 85, issue 1, 2010.
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Affiliation(s)
- Koen K A Van Rompay
- California National Primate Research Center, University of California, Davis, CA 95616, USA.
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Fehér A, Boross P, Sperka T, Miklóssy G, Kádas J, Bagossi P, Oroszlan S, Weber IT, Tözsér J. Characterization of the murine leukemia virus protease and its comparison with the human immunodeficiency virus type 1 protease. J Gen Virol 2006; 87:1321-1330. [PMID: 16603535 DOI: 10.1099/vir.0.81382-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The protease (PR) of Murine leukemia virus (MLV) was expressed in Escherichia coli, purified to homogeneity and characterized by using various assay methods, including HPLC-based, photometric and fluorometric activity measurements. The specificity of the bacterially expressed PR was similar to that of virion-extracted PR. Compared with human immunodeficiency virus type 1 (HIV-1) PR, the pH optimum of the MLV enzyme was higher. The specificity of the MLV PR was further compared with that of HIV-1 PR by using various oligopeptides representing naturally occurring cleavage sites in MLV and HIV-1, as well as by using bacterially expressed proteins having part of the MLV Gag. Inhibitors designed against HIV-1 PR were also active on MLV PR, although all of the tested ones were substantially less potent on this enzyme than on HIV-1 PR. Nevertheless, amprenavir, the most potent inhibitor against MLV PR, was also able to block Gag processing in MLV-infected cells. These results indicate that, in spite of the similar function in the life cycle of virus infection, the two PRs are only distantly related in their specificity.
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Affiliation(s)
- Anita Fehér
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Hungary
| | - Péter Boross
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Hungary
| | - Tamás Sperka
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Hungary
| | - Gabriella Miklóssy
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Hungary
| | - János Kádas
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Hungary
| | - Péter Bagossi
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Hungary
| | - Stephen Oroszlan
- HIV Drug Resistant Program, National Cancer Institute at Frederick, MD, USA
| | - Irene T Weber
- Department of Biology, Georgia State University, Atlanta, GA, USA
| | - József Tözsér
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Hungary
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Fehér A, Boross P, Sperka T, Oroszlan S, Tözsér J. Expression of the murine leukemia virus protease in fusion with maltose-binding protein in Escherichia coli. Protein Expr Purif 2004; 35:62-8. [PMID: 15039067 DOI: 10.1016/j.pep.2004.01.008] [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] [Received: 09/30/2003] [Revised: 01/12/2004] [Indexed: 01/15/2023]
Abstract
The protease of murine leukemia virus (MLV) was cloned into pMal-c2 vector, expressed in fusion with maltose-binding protein (MBP), and purified to homogeneity after Factor Xa cleavage of the chimeric protein. Substantial degradation of the fusion protein was observed during expression, which severely diminished the yield. The degree of degradation of the fusion protein was even more pronounced when a single-chain form of the MLV protease was cloned after the gene coding for MBP. To increase the yield, a hexahistidine tag with an additional Factor Xa cleavage site was cloned after the protease and nickel chelate affinity chromatography was used as the first purification step. The modified procedure resulted in substantially higher yield as compared to the original procedure. The degradation of hexahistidine-tagged active site mutant MLV protease was very low and comparable to that obtained with hexahistidine-tagged MBP, but purified MLV protease alone was not able to degrade purified MBP, suggesting that during expression the active MLV protease may activate bacterial proteases which appear to be responsible for the degradation of the fusion proteins.
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Affiliation(s)
- Anita Fehér
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
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Giuffre AC, Higgins J, Buckheit RW, North TW. Susceptibilities of simian immunodeficiency virus to protease inhibitors. Antimicrob Agents Chemother 2003; 47:1756-9. [PMID: 12709355 PMCID: PMC153320 DOI: 10.1128/aac.47.5.1756-1759.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We used a focal infectivity assay with HeLa H1-JC.37 cells to directly compare susceptibilities of simian immunodeficiency virus (SIV) and human immunodeficiency virus type 1 (HIV-1) to protease inhibitors. SIVmac239 was inhibited by indinavir, saquinavir, and ritonavir, with 50% effective concentrations (means +/- standard deviations) of 39 +/- 8, 55 +/- 3, and 13 +/- 5 nM, respectively. The corresponding values for inhibition of HIV-1 were 66 +/- 4, 47 +/- 10, and 25 +/- 14 nM, respectively.
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Affiliation(s)
- Angelica C Giuffre
- Center for Comparative Medicine, Department of Veterinary Molecular Biosciences, University of California, Davis, Davis, California 95616, USA
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Qari SH, Magre S, García-Lerma JG, Hussain AI, Takeuchi Y, Patience C, Weiss RA, Heneine W. Susceptibility of the porcine endogenous retrovirus to reverse transcriptase and protease inhibitors. J Virol 2001; 75:1048-53. [PMID: 11134319 PMCID: PMC114002 DOI: 10.1128/jvi.75.2.1048-1053.2001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Porcine xenografts may offer a solution to the shortage of human donor allografts. However, all pigs contain the porcine endogenous retrovirus (PERV), raising concerns regarding the transmission of PERV and the possible development of disease in xenotransplant recipients. We evaluated 11 antiretroviral drugs licensed for human immunodeficiency virus type 1 (HIV-1) therapy for their activities against PERV to assess their potential for clinical use. Fifty and 90% inhibitory concentrations (IC(50)s and IC(90)s, respectively) of five nucleoside reverse transcriptase inhibitors (RTIs) were determined enzymatically for PERV and for wild-type (WT) and RTI-resistant HIV-1 reference isolates. In a comparison of IC(50)s, the susceptibilities of PERV RT to lamivudine, stavudine, didanosine, zalcitabine, and zidovudine were reduced >20-fold, 26-fold, 6-fold, 4-fold, and 3-fold, respectively, compared to those of WT HIV-1. PERV was also resistant to nevirapine. Tissue culture-based, single-round infection assays using replication-competent virus confirmed the relative sensitivity of PERV to zidovudine and its resistance to all other RTIs. A Gag polyprotein-processing inhibition assay was developed and used to assess the activities of protease inhibitors against PERV. No inhibition of PERV protease was seen with saquinavir, ritonavir, indinavir, nelfinavir, or amprenavir at concentrations >200-fold the IC(50)s for WT HIV-1. Thus, following screening of many antiretroviral agents, our findings support only the potential clinical use of zidovudine.
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Affiliation(s)
- S H Qari
- HIV and Retrovirology Branch, Division of AIDS, STD, and TB Laboratory Research, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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White EL, Westbrook L, Hollingshead MG, Shannon WM. Optimization of the reverse transcriptase assay for the detection of viral burden in mice infected with Rauscher murine leukemia virus. J Virol Methods 1996; 62:63-70. [PMID: 8910649 DOI: 10.1016/0166-0934(96)02089-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Rauscher murine leukemia virus induces an erythroleukemia in susceptible strains of mice that is associated with splenomegaly and viremia. This animal model has been used for evaluating the in vivo efficacy of potential anti-HIV agents. The in vivo antiviral activity of therapeutic agents has usually been determined by measuring a reduction in the spleen weights of compound-treated mice or by quantitating viremia with the UV-XC plaque assay. The UV-XC assay, however, is time-consuming and labor-intensive. Virions of Rauscher murine leukemia virus, like other retroviruses, contain the enzyme reverse transcriptase. Quantitating the level of this enzyme in infected mouse sera provides a more rapid measure of viremia in the animal. We have examined the effects of several reagents, including detergent, KCl, EGTA, dGMP, spermine, as well as protease and RNase inhibitors, on the reverse transcriptase assay. The optimized assay method was effective in evaluating the antiviral activity of AZT in the Rauscher murine leukemia virus in vivo model. The assay is also amenable to automation if large numbers of assays are required.
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Affiliation(s)
- E L White
- Southern Research Institute, Birmingham, AL 35205, USA.
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Cherrington JM, Fuller MD, Mulato AS, Allen SJ, Kunder SC, Ussery MA, Lesnikowski Z, Schinazi RF, Sommadossi JP, Chen MS. Comparative kinetic analyses of interaction of inhibitors with Rauscher murine leukemia virus and human immunodeficiency virus reverse transcriptases. Antimicrob Agents Chemother 1996; 40:1270-3. [PMID: 8723481 PMCID: PMC163306 DOI: 10.1128/aac.40.5.1270] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The inhibitory effects of several nucleoside triphosphate analogs on Rauscher murine leukemia virus (RMuLV) and human immunodeficiency virus (HIV) type 1 reverse transcriptases (RTs) were studied. With RNA as the template, the apparent K(m) and apparent K(i) values of HIV RT toward its substrates and inhibitors are 12 to 500 times lower than the corresponding values for RMuLV RT. However, the k(i)/k(m) ratios (inhibition efficiencies) for HIV and RMuLV RTs'are similar for AZTTP (zidovudine triphosphate), d4TTP [3'-deoxythymidine-2'-ene-(3'-deoxy-2',3'-didehydrothymidine) triphosphate], PMEADP [9-(2-phosphonylmethoxyethyl)adenine diphosphate], FIAUTP [1-(2-fluoro-2-deoxy-beta-D-arabinofuranosyl)-5-iodouracil triphosphate], and HPMPCDP [(S)-1-(3-hydroxy-2-phosphylmethoxypropyl) cytosine diphosphate]. With DNA as the template, the K(m) values are similar for HIV and RMuLV RTs. However, the K(i)/K(m) values of HIV and RMuLV RTs are significantly different for ddCTP, ddATP, and 3TCTP (2',3'-dideoxy-3'-thiacytidine). The RTs of RMuLV and HIV are sufficiently different from one another that the kinetic inhibition constants for a particular antiviral compounds should be determined to indicate whether anti-RMuLV activity is likely to be predictive for the anti-HIV activity of the compound. This information, in conjunction with species-specific drug metabolism differences and tissue culture antiviral activity, is important in determining the suitability of a particular animal model.
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Black PL, Ussery MA, Barney S, Wittrock R, DeMarsh P, Dreyer GB, Petteway SR, DalMonte P, Baldoni J, Lambert D. Effects of SKF 108922, an HIV-1 protease inhibitor, on retrovirus replication in mice. Antiviral Res 1996; 29:175-86. [PMID: 8739597 DOI: 10.1016/0166-3542(95)00831-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Rationally designed synthetic inhibitors of retroviral proteases inhibit the processing of viral polypeptides in cultures of human T lymphocytes infected with human immunodeficiency virus type 1 (HIV-1) and therefore suppress the infectivity of HIV-1 in vitro. We have previously reported the antiviral activity in vitro of HIV-1 protease inhibitors against the C-type retrovirus Rauscher murine leukemia virus (RMuLV) and the lentivirus simian immunodeficiency virus (SIV). The same compounds which blocked the infectivity of HIV-1 also inhibited the infectivity of RMuLV and SIV in vitro. This report extends these findings by testing the antiviral activity of HIV-1 protease inhibitors in vivo in the RMuLV model. RMuLV-infected mice were treated twice a day (bid) with either an active (SKF 108922) or inactive (SKF 109273) compound for fourteen days by the intraperitoneal (i.p.) route. Compared with excipient control, SKF 108922, formulated with hydroxypropyl-beta-cyclodextrin (HPB), reduced virus-induced splenomegaly, viremia, and serum reverse transcriptase (RT) levels, while SKF 109273 was inactive. The HPB vehicle by itself enhanced replication of RMuLV. The effects of changing the formulation and the route of administration were examined. SKF 108922, formulated in HPB, had similar antiviral activity when administered by the i.p. or subcutaneous (SC) routes. However, SKF 108922 administered as a colloidal suspension in cholesterol sulfate (CS) had no detectable antiviral effect. Measurements of the circulating levels of the protease inhibitor in plasma explained this result. Plasma concentrations of SKF 108922 exceeded 1000 nM within 10 min after SC administration of the compound solubilized in HPB, but SKF 108922 was not detected in plasma after SC administration of the same dose formulated with CS. Information on optimal conditions for administering these agents should prove useful in guiding their clinical application Therefore, RMuLV should provide a good model for the preclinical evaluation and development of this class of agents for the treatment of HIV.
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Affiliation(s)
- P l Black
- Division of Antiviral Drug Products, Center for Drug Evaluation and Research, HFD-535, US Food and Drug Administration, Rockville, MD 20857, USA
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Pillay D, Bryant M, Getman D, Richman DD. HIV-1 Protease inhibitors: Their development, mechanism of action and clinical potential. Rev Med Virol 1995. [DOI: 10.1002/rmv.1980050104] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Martin JA, Redshaw S, Thomas GJ. Inhibitors of HIV proteinase. PROGRESS IN MEDICINAL CHEMISTRY 1995; 32:239-87. [PMID: 8577919 DOI: 10.1016/s0079-6468(08)70455-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- J A Martin
- Roche Products Ltd., Welwyn Garden City, Herts, UK
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