Advertisement
Research Article| Volume 14, ISSUE 2, P393-422, June 1994

HIV-1 Drug Resistance: Molecular Pathogenesis and Laboratory Monitoring

  • Richard T. D’Aquila
    Correspondence
    Address reprint requests to Richard T. D’Aquila, MD, Infectious Disease Unit, Massachusetts General Hospital, 149 13th Street, Charlestown, MA 02129.
    Affiliations
    From the Infectious Disease Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
    Search for articles by this author
      This paper is only available as a PDF. To read, Please Download here.
      Molecular and clinical aspects of HIV-1 pathogenesis are described, including the turnover of the HIV-1 population in vivo, the clinical significance of resistance to HIV-1 reverse transcriptase (RT) inhibitors, and the inter-relationship between virus replication and RT inhibitor resistance. The molecular genetics of RT inhibitor resistance, including interactive effects of different RT mutations and the implications of those effects for combination chemotherapy, are summarized. Structural studies of RT and the biochemical bases of drug resistance are discussed.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribers receive full online access to your subscription and archive of back issues up to and including 2002.

      Content published before 2002 is available via pay-per-view purchase only.

      Subscribe:

      Subscribe to Clinics in Laboratory Medicine
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Adams J.
        • Klunder J.
        • Tong L.
        • et al.
        Structural analysis of the non-nucleoside binding site of HIV-1 reverse transcriptase.
        in: Second International HIV Drug-Resistance Workshop. Noordwijk, The Netherlands1993: 23
        • Arnold E.
        • Jacobo M.A.
        • Nanni R.G.
        • et al.
        Structure of HIV-1 reverse transcriptase/DNA complex at 7 A resolution showing active site locations.
        Nature. 1992; 357: 85-89
        • Baba M.
        • DeClerq E.
        • Tanaka H.
        • et al.
        Potent and selective inhibition of human immunodeficiency virus type 1 (HIV-1) by 5-ethyl-6-phenylthiouracil derivatives through their interaction with the HIV-1 reverse transcriptase.
        Proc Natl Acad Sci USA. 1991; 88: 2356-2369
        • Bacolla A.
        • Shih C.K.
        • Rose J.M.
        • et al.
        Amino acid substitutions in HIV-1 reverse transcriptase with corresponding residues from HIV-2: Effect on kinetic constants and inhibition by non-nucleoside analogs.
        J Biol Chem. 1993; 268: 16571-16577
        • Bagasra O.
        • Hauptman S.P.
        • Lischner H.W.
        • et al.
        Detection of human immunodeficiency virus type 1 pro virus in mononuclear cells by in situ polymerase chain reaction.
        N Engl J Med. 1992; 326: 1385-1391
        • Balzarini J.
        • Karlsson A.
        • De Clerq E.
        Human immunodeficiency virus type 1 drug-resistance patterns with different l-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine derivatives.
        Mol Pharmacol. 1993; 44: 694-701
        • Balzarini J.
        • Karlsson A.
        • Perez-Perez M.J.
        • et al.
        Treatment of human immunodeficiency virus type 1 (HIV-1)-infected cells with combinations of HIV-l-specific inhibitors results in a different resistance pattern than does treatment with single-drug therapy.
        J Virol. 1993; 67: 5353-5359
        • Balzarini J.
        • Karlsson A.
        • Perez-Perez M.J.
        • et al.
        HIV-l-specific reverse transcriptase inhibitors show differential activity against HIV-1 mutant strains containing different amino acid substitutions in the reverse transcriptase.
        Virology. 1993; 192: 246-253
        • Balzarini J.
        • Karlsson A.
        • Vandamme A.M.
        • et al.
        Human immunodeficiency virus type 1 (HIV-1) strains selected for resistance against the HIV-l-specific [2′,5′-bis-O-(tert-butyldimethylsilyl)-3′-spiro-5″-(4″-amino-1″, 2″-oxathiole-2″, 2″-dioxide)]-beta-D-pentofuranosyl (TSAO) nucleoside analogues retain sensitivity to HIV-l-specific nonnucleoside inhibitors.
        Proc Natl Acad Sci USA. 1993; 90: 6952-6956
        • Balzarini J.
        • Perez-Perez M.J.
        • San F.A.
        • et al.
        2′,5′-bis-O-(tert-butyldimethylsilyl)-3′-spiro-5″-(4″-amino-1″, 2″-oxathiole-2″, 2′-dioxide)pyrimidine (TSAO) nucleoside analogues: Highly selective inhibitors of human immunodeficiency virus type 1 that are targeted at the viral reverse transcriptase.
        Proc Natl Acad Sci USA. 1992; 89: 4392-4396
        • Balzarini J.
        • Velazquez S.
        • San Felix A.
        • et al.
        Human immunodeficiency virus type 1-specific [2′, 5′-bis-O-(tert-butyldimethylsilyl)-beta-D-ribofuranosyl]-3′-spiro-5″ (4″-amino-1″, 2″-oxathiole-2″, 2″-dioxide)-purine analogues show a resistance spectrum that is different from that of the human immunodeficiency virus type 1-specific non-nucleoside analogues.
        Mol Pharmacol. 1993; 43: 109-114
        • Boucher C.
        • Tersmette M.
        • Lange J.
        • et al.
        Zidovudine sensitivity of human immunodeficiency viruses from high-risk, symptom free individuals during therapy.
        Lancet. 1990; 336: 585-590
        • Boucher C.A.B.
        • Cammack N.
        • Schipper P.
        • et al.
        High-level resistance to (−) enantiomeric 2′-deoxy-3′-thiacytidine in vitro is due to one amino acid substitution in the catalytic site of human immunodeficiency virus type 1 reverse transcriptase.
        Anti-microb Agents Chemother. 1993; 37: 2231-2234
        • Boucher C.A.B.
        • Lange J.M.A.
        • Miedema F.F.
        • et al.
        HIV-1 biologic phenotype and the development of zidovudine resistance in relation to disease progression in asymptomatic individuals during treatment.
        AIDS. 1992; 6: 1259-1264
        • Boucher C.A.B.
        • O’Sullivan E.
        • Mulder J.W.
        • et al.
        Ordered appearance of zidovudine resistance mutations during treatment of 18 human immunodeficiency virus-positive subjects.
        J Infect Dis. 1992; 165: 105-110
        • Boucher C.A.B.
        • van Leeuwen R.
        • Kellam P.
        • et al.
        Effects of discontinuation of zidovudine treatment on zidovudine sensitivity of human immunodeficiency virus type 1 isolates.
        Antimicrob Agents Chemother. 1993; 37: 1525-1530
        • Boyer P.L.
        • Currens M.J.
        • McMahon J.B.
        • et al.
        Analysis of nonnucleoside drug-resistant variants of human immunodeficiency virus type 1 reverse transcriptase.
        J Virol. 1993; 67: 2412-2420
        • Boyer P.L.
        • Ferris A.L.
        • Hughes S.H.
        Cassette mutagenesis of the reverse transcriptase of human immunodeficiency virus type 1.
        J Virol. 1992; 66: 1031-1039
        • Boyer P.L.
        • Ferris A.L.
        • Hughes S.H.
        Mutational analysis of the fingers domain of HIV-1 RT.
        J Virol. 1992; 66: 7533-7537
      1. Boyer PL, Tantillo C, Jacobo-Molina A, et al: Structural and biochemical analysis shows nucleoside analog resistance of HIV-1 RT variants involves alterations in template: primer positioning. In Fifth International Conference of the National Cooperative Drug Discovery Groups for the Treatment of HIV Infection, Washington, DC, 1993, p 45

        • Brun-Vezinet F.
        • Ingrand D.
        • Deforges L.
        • et al.
        HIV-1 sensitivity to zidovudine: A consensus culture technique validated by genotypic analysis of the reverse transcriptase.
        J Virol Methods. 1992; 37: 177-188
        • Burger H.
        • Weiser B.
        • Flaherty K.
        • et al.
        Evolution of human immunodeficiency virus type 1 sequence diversity among close contacts.
        Proc Natl Acad Sci USA. 1991; 88: 11236-11240
      2. Byrnes VW, Emini EA, Staszewski S, et al: Combination therapy with AZT prevents selection of HIV-1 variants that are highly resistant to the nonnucleoside reverse transcriptase inhibitor L-697, 661 [abstract WS-A19-5]. In IXth International AIDS Conference, Berlin, Germany, 1993

        • Byrnes V.W.
        • Sardana V.V.
        • Schleif W.A.
        • et al.
        Comprehensive mutant enzyme and viral variant assessment of human immunodeficiency virus type 1 reverse transcriptase resistance to nonnucleoside inhibitors.
        Antimicrob Agents Chemother. 1993; 37: 1576-1579
        • Campbell T.B.
        • Young R.K.
        • Eron J.J.
        • et al.
        Inhibition of human immunodeficiency virus type 1 replication in vitro by the bisheteroarylpiperazine atevirdine (U-87201E) in combination with zidovudine or didanosine.
        J Infect Dis. 1993; 168: 318-326
      3. Cavert W, Coombs RW, Kuritzkes D, et al: Baseline zidovudine susceptibility, codon 215 mutation, viral load, and syncytium-inducing characteristics of HIV isolates from ACTG protocol 194 [abstract 464a]. In First National Conference on Human Retroviruses and Related Infections, Washington, DC, 1993, p 137

        • Chesebro B.
        • Wehrly K.
        Development of a sensitive quantitative focal assay for human immunodeficiency virus infectivity.
        J Virol. 1988; 62: 3779-3788
        • Chow Y-K
        • Hirsch M.S.
        • Merrill D.P.
        • et al.
        Use of evolutionary limitations of HIV-1 multi-drug resistance to optimize therapy.
        Nature. 1993; 361: 650-654
        • Coffin J.M.
        Genetic variation in retroviruses.
        in: Kurstak E. Applied Virology Research. Plenum Press, New York1990: 11-33
        • Coffin J.M.
        Genetic diversity and evolution of retroviruses.
        Curr Top Microbiol Immunol. 1992; 176: 143-164
        • Coffin J.M.
        Reverse transcription and evolution.
        in: Skalka A.M. Goff S.P. Reverse Transcriptase. Cold Spring Harbor Laboratory Press, Plainview, NY1993: 445-479
        • Condra J.H.
        • Emini E.A.
        • Gotlib L.
        • et al.
        Identification of the human immunodeficiency virus reverse transcriptase residues that contribute to the activity of diverse nonnucleoside inhibitors.
        Antimicrob Agents Chemother. 1992; 36: 1441-1446
      4. D’Aquila R, Johnson V, Kuritzkes D, et al: HIV-1 drug resistance and syncytium-inducing phenotype: Associations with disease progression among ACTG 116B/117 subjects. Presented at the IXth International Conference on AIDS. Berlin, Germany, PO-B26-2046, 1993

        • de Bethune M-P
        • Pauwels R.
        • Andries K.
        • et al.
        AZT resistance reversal by the nonnucleoside reverse transcriptase inhibitor alpha-APA R18893 in a symptomatic HIV-infected individual.
        in: Second International HIV Drug-Resistance Workshop. Noordwijk, The Netherlands1993
        • Dimitrov D.H.
        • Hollinger F.B.
        • Baker C.J.
        • et al.
        Study of human immunodeficiency virus resistance to 2′-3′-dideoxyinosine and zidovudine in sequential isolates from pediatric patients on long-term therapy.
        J Infect Dis. 1993; 167: 818-823
        • Duewecke T.J.
        • Pushkarskaya T.J.
        • Poppe S.M.
        • et al.
        A novel mutation in bisheteroarylpiperazine-resistant HIV-1 reverse transcriptase confers increased sensitivity to other nonnucleoside inhibitors.
        Proc Natl Acad Sci USA. 1993; 90: 4713-4717
        • Edlin B.R.
        • St Clair M.H.
        • Pitha P.M.
        • et al.
        In-vitro resistance to zidovudine and alpha-interferon in HIV-1 isolates from patients: Correlations with treatment duration and response.
        Ann Intern Med. 1992; 117: 457-460
        • Eigen M.
        • Biebricher C.K.
        Sequence space and quasispecies distribution.
        in: Domingo E. RNA Genetics. CRC Press, Boca Raton, FL1988: 3-22
        • Embretson J.
        • Zupanic M.
        • Ribas J.L.
        • et al.
        Massive covert infection of helper T lymphocytes and macrophages by HIV during the incubation period of AIDS.
        Nature. 1993; 362: 359-362
        • Emini E.
        • Graham D.J.
        • Gotlib L.
        • et al.
        HIV and multidrug resistance.
        Nature. 1993; 364: 679
        • Erice A.
        • Mayers D.L.
        • Strike D.G.
        • et al.
        Brief report: Primary infection with zidovudine-resistant human immunodeficiency virus type 1.
        N Engl J Med. 1993; 328: 1163-1165
        • Eron J.J.
        • Chow Y-K
        • Caliendo A.M.
        • et al.
        pol mutations conferring zidovudine and didanosine resistance with different effects in vitro yield multiply resistant human immunodeficiency virus type 1 isolates in vivo.
        Antimicrob Agents Chemother. 1993; 37: 1480-1487
        • Eron J.J.
        • Gorczyca P.
        • Kaplan J.C.
        • et al.
        Susceptibility testing by polymerase chain reaction DNA quantitation: A method to measure drug resistance of human immunodeficiency virus type 1 isolates.
        Proc Nat Acad Sci USA. 1992; 89: 3241-3245
      5. Fitzgibbon J, Farnham A, Sperber S, et al: AZT and ddC resistance mutations in HIV from a patient treated with both agents. In The 32nd Interscience Conference on Antimicrobial Agents and Chemotherapy, Anaheim, CA, 1992, p 206

        • Fitzgibbon J.E.
        • Gaur S.
        • Frenkel L.D.
        • et al.
        Transmission from one child to another of human immunodeficiency virus type 1 with a zidovudine-resistance mutation.
        N Engl J Med. 1993; 329: 1835-1841
        • Fitzgibbon J.E.
        • Howell R.M.
        • Haberzettl C.A.
        • et al.
        Human immunodeficiency virus type 1 pol gene mutations which cause decreased susceptibility to 2′, 3′-dideoxycytidine.
        Antimicrob Agents Chemother. 1992; 36: 153-157
      6. Frenkel LM, Wagner L, Atwood S, et al: A rapid, sensitive assay for the detection of didanosine (ddI) resistance associated mutation at the pol amino acid 74. In Third Workshop on Viral Resistance, Gaithersburg, MD, 1993

        • Gao Q.
        • Gu Z.
        • Parniak M.A.
        • et al.
        The same mutation that encodes low-level human immunodeficiency virus type 1 resistance to 2′,3′-dideoxyinosine and 2′, 3′-dideoxycytidine confers high level resistance to the (−) enantiomer of 2′, 3′-dideoxy-3′-thiacytidine.
        Antimicrob Agents Chemother. 1993; 37: 1390-1392
        • Gao Q.
        • Gu Z.
        • Parniak M.A.
        • et al.
        In vitro selection of variants of human immunodeficiency virus type 1 resistant to 3′-azido-3′-deoxythymidine and 2′,3′-dideoxyinosine.
        J Virol. 1992; 66: 12-19
        • Gingeras T.R.
        • Propandovich P.
        • Latimer T.
        • et al.
        Use of self-sustained sequence replication amplification reaction to analyze and detect mutations in zidovudine resistant HIV.
        J Infect Dis. 1991; 164: 1066-1074
        • Goldman M.E.
        • Nunberg J.H.
        • O’Brien J.A.
        • et al.
        Pyridinone derivatives: Specific human immunodeficiency virus type 1 reverse transcriptase inhibitors with antiviral activity.
        Proc Natl Acad Sci USA. 1991; 88: 6863-6867
        • Goldman M.E.
        • O’Brien J.A.
        • Ruffing T.L.
        • et al.
        A nonnucleoside reverse transcriptase inhibitor active on human immunodeficiency virus type 1 isolates resistant to related inhibitors.
        Antimicrob Agents Chemother. 1993; 37: 947-949
        • Goodenow M.
        • Huet T.
        • Saurin W.
        • et al.
        HIV-1 isolates are rapidly evolving quasispecies: Evidence for viral mixtures and preferred nucleotide substitutions.
        J AIDS. 1989; 2: 344-352
      7. Gu X, Gao Q, Salomon H, et al: A novel mutation at codon 50 in the HIV-1 pol gene that encodes resistance to 2′, 3′-didehydro-3′-deoxythymidine (d4T) [abstract 463]. In First National Conference on Human Retroviruses and Related Infections, Washington, DC, 1993, p 137

        • Gu Z.
        • Gao Q.
        • Fang H.
        • et al.
        Identification of a mutation at codon 65 in the IKKK motif of reverse transcriptase that encodes human immunodeficiency virus resistance to 2′, 3′-dideoxycytidine and 2′, 3′-deoxythiacytidine.
        Antimicrob Agents Chemother. 1994; 38: L75-L81
      8. Gu Z, Gao Q, Li X, et al: Novel mutation in the human immunodeficiency virus type 1 reverse transcriptase gene that encodes cross-resistance to 2′,3′-dideoxyinosine and 2′, 3′-dideoxycytidine. J Virol 66, 1992

        • Hahn B.H.
        • Shaw G.M.
        • Taylor M.E.
        • et al.
        Genetic variation in HTLV-III/LAV over time in patients with AIDS or at risk for AIDS.
        Science. 1986; 232: 1548-1553
        • Hammer S.
        • Crumpacker C.
        • D’Aquila R.
        • et al.
        Use of virologic assays for detection of human immunodeficiency virus in clinical trials: Recommendations of the AIDS Clinical Trials Group Virology Committee.
        J Clin Microbiol. 1993; 31: 2557-2564
      9. Havlir D, for the ACTG 164 and 168 Study Teams: Antiviral activity of nevirapine at 400 mg in p24 antigen positive adults [abstract WS-B26-1]. In IXth International Conference on AIDS, Berlin, Germany, 1993

        • Ho D.D.
        • Moudgil T.
        • Alam M.
        Quantitation of HIV-1 in the blood of infected persons.
        N Engl J Med. 1989; 321: 1621-1625
        • Holland J.J.
        • De La Torre J.C.
        • Steinhauer D.A.
        RNA virus populations as quasispecies.
        Curr Top Microbiol Immunol. 1992; 176: 1-20
        • Holmes E.C.
        • Zhang L.Q.
        • Simmonds P.
        • et al.
        Convergent and divergent sequence evolution in the surface envelope glycoprotein of human immunodeficiency virus type 1 with a single infected patient.
        Proc Natl Acad Sci USA. 1992; 89: 4835-4839
      10. Hooker DJ, Gurusinghe AD, Land SA, et al: Novel mutation associated with HIV-1 resistance to AZT [abstract 464]. In First National Conference on Human Retroviruses and Related Infections, Washington, DC, 1993, p 137

        • Husson R.N.
        • Shirasaka T.
        • Butler K.M.
        • et al.
        High-level resistance to zidovudine but not to zalcitabine or didanosine in human immunodeficiency virus from children receiving antiretroviral therapy.
        J Pediatr. 1993; 123: 9-16
        • Jacobo-Molina A.
        • Ding J.
        • Nanni R.G.
        • et al.
        Crystal structure of human immunodeficiency virus type 1 reverse transcriptase complexed with double-stranded DNA at 3.0 A resolution shows bent DNA.
        Proc Natl Acad Sci USA. 1993; 90: 6320-6324
      11. Jacobsen H, Craig CJ, Duncan IB, et al: In vitro selection and characterisation of HIV-1 variants with reduced sensitivity to a proteinase inhibitor. In IXth International Conference on AIDS, Berlin, Germany, 1993

        • Japour A.
        • Chatis P.
        • Eigenrauch H.
        • et al.
        Detection of human immunodeficiency virus type 1 clinical isolates with reduced sensitivity to zidovudine and dideoxyinosine by RNA-RNA hybridization.
        Proc Natl Acad Sci USA. 1991; 88: 3092-3096
        • Japour A.J.
        • Mayers D.L.
        • Johnson V.A.
        • et al.
        A standardized peripheral blood mononuclear cell culture assay for the determination of drug susceptibilites of clinical human immunodeficiency virus (HIV-1) isolates.
        Antimicrob Agents Chemother. 1993; 37: 1095-1101
        • Johnson V.A.
        • Merrill D.P.
        • Videler J.A.
        • et al.
        Two-drug combinations of zidovudine, didanosine, and recombinant interferon-alpha A inhibit replication of zidovudine-resistant human immunodeficiency virus type 1 synergistically in vitro.
        J Infect Dis. 1991; 164: 646-655
        • Juiken C.L.
        • de Jong J-J
        • Baan E.
        • et al.
        Evolution of the V3 envelope domain in proviral sequences and isolates of human immunodeficiency virus type 1 during transition of the viral biologic phenotype.
        J Virol. 1992; 66: 4622-4627
        • Jung M.
        • Agut H.
        • Candotti D.
        • et al.
        Susceptibility of HIV-1 isolates to zidovudine: Correlation between widely applicable culture test and PCR analysis.
        J AIDS. 1992; 5: 359-364
        • Kahn J.O.
        • Lagakos S.W.
        • Richman D.D.
        • et al.
        A controlled trial comparing continued zidovudine with didanosine in human immunodeficiency virus infection.
        N Engl J Med. 1992; 327: 581-587
        • Kashman Y.
        • Gustafson K.R.
        • Fuller R.W.
        • et al.
        The calanolides, a novel HIV-inhibitory class of coumarin derivatives from the tropical rainforest tree, Calophyllum lanigerum.
        J Med Chem. 1992; 35: 2735-2743
        • Katz R.A.
        • Skalka A.M.
        Generation of diversity in retroviruses.
        Ann Rev Genet. 1990; 24: 409-445
        • Kaye S.
        • Loveday C.
        • Tedder R.S.
        A microtitre format point mutation assay: Application to the detection of drug resistance in human immunodeficiency virus type-1 infected patients treated with zidovudine.
        J Med Virol. 1992; 37: 241-246
        • Kellam P.
        • Boucher C.A.B.
        • Larder B.A.
        Fifth mutation in human immunodeficiency virus type 1 reverse transcriptase contributes to the development of high-level resistance to zidovudine.
        Proc Nat Acad Sci USA. 1992; 89: 1934-1938
        • Kellam P.
        • Larder B.A.
        Recombinant virus assav.
        Antimicrob Agents Chemother. 1994; 38: 23-30
        • Kleim J-P
        • Bender R.
        • Billhardt U-M
        • et al.
        Activity of a novel quinoxaline derivative against human immunodeficiency virus type 1 reverse transcriptase and viral replication.
        Antimicrob Agents Chemother. 1993; 37: 1659-1664
        • Kohlstaedt L.A.
        • Wang J.
        • Friedman J.M.
        • et al.
        Crystal structure at 3.5 Å resolution of HIV-1 reverse transcriptase complexed with an inhibitor.
        Science. 1992; 256: 1783-1790
        • Koot M.
        • Keet I.P.M.
        • Vos H.V.
        • et al.
        Prognostic value of HIV-1 syncytium-inducing phenotype for rate of CD4+ cell depletion and progression to AIDS.
        Ann Intern Med. 1993; 118: 681-688
        • Kopp E.B.
        • Miglietta J.J.
        • Shrutkowski A.G.
        • et al.
        Steady state kinetics and inhibition of HIV-1 reverse transcriptase by a non-nucleoside dipyridodiazepinone, BI-RG-587, using a heteropolymeric template.
        Nucleic Acids Res. 1991; 19: 3035-3039
        • Kozal M.J.
        • Shafer R.W.
        • Winters M.A.
        • et al.
        A mutation in human immunodeficiency virus reverse transcriptase and decline in CD4 lymphocyte numbers in long-term zidovudine recipients.
        J Infect Dis. 1993; 167: 526-532
        • Lacey S.F.
        • Larder B.A.
        In vitro selection of HIV-1 resistance to d4T.
        in: Second International HIV Drug-Resistance Workshop. Noordwijk, The Netherlands1993: 11
        • Lacey S.F.
        • Reardon J.E.
        • Furfine E.S.
        • et al.
        Biochemical studies of the reverse transcriptase and RNase H activities from human immunodeficiency virus strains resistant to 3′-azido-3′-deoxythymidine.
        J Biol Chem. 1992; 267: 15789-15794
        • Land S.
        • Treloar G.
        • McPhee D.
        Decreased in vitro susceptibility to zidovudine of HIV isolates obtained from patients with AIDS.
        J Infect Dis. 1990; 161: 326-329
        • Larder B.
        • Chesebro B.
        • Richman D.
        Susceptibilities of zidovudine-susceptible and resistant human immunodeficiency virus isolates to antiviral agents determined by using a quantitative plaque reduction assay.
        Antimicrob Agents Chemother. 1990; 34: 436-441
        • Larder B.A.
        3′-azido-3′-deoxythymidine resistance suppressed by a mutation conferring human immunodeficiency virus type 1 resistance to nonnucleoside reverse transcriptase inhibitors.
        Antimicrob Agents Chemother. 1992; 36: 2664-2669
        • Larder B.A.
        Inhibitors of HIV reverse transcriptase as antiviral agents and drug resistance.
        in: Skalka A.M. Goff S.P. Reverse Transcriptase. Cold Spring Harbor Laboratory Press, Plain view, NY1993: 205-222
        • Larder B.A.
        • Coates K.E.
        • Kemp S.D.
        Zidovudine-resistant human immunodeficiency virus selected by passage in cell culture.
        J Virol. 1991; 65: 5232-5236
        • Larder B.A.
        • Darby G.
        • Richman D.D.
        HIV with reduced sensitivity to zidovudine (AZT) isolated during prolonged therapy.
        Science. 1989; 243: 1731-1734
        • Larder B.A.
        • Kellam P.
        • Kemp S.D.
        Zidovudine resistance predicted by direct detection of mutations in DNA from HIV-infected lymphocytes.
        AIDS. 1991; 5: 137-144
        • Larder B.A.
        • Kellam P.
        • Kemp S.D.
        Convergent combination therapy can select viable multi-drug resistant HIV-1 in vitro.
        Nature. 1993; 365: 451-453
        • Larder B.A.
        • Kemp S.D.
        Multiple mutations in the HIV-1 reverse transcriptase confer high-level resistance to zidovudine (AZT).
        Science. 1989; 246: 1155-1158
        • Larder B.A.
        • Kemp S.D.
        • Purifoy D.J.M.
        Infectious potential of human immunodeficiency type 1 reverse transcriptase mutants with altered inhibitor sensitivity.
        Proc Natl Acad Sci USA. 1989; 86: 4803-4807
        • Larder B.A.
        • Kohli A.
        • Kellam P.
        • et al.
        Quantitative detection of HIV-1 drug resistance mutations by automated DNA sequencing.
        Nature. 1993; 365: 671-673
        • Larder B.A.
        • Purifoy D.J.M.
        • Powell K.L.
        • et al.
        Site-specific mutagenesis of AIDS virus reverse transcriptase.
        Nature. 1987; 327: 716-717
        • Levantis P.
        • Oxford J.S.
        Molecular aspects of AZT resistance in HIV-1.
        Res Virol. 1992; 143: 136-142
      12. Lin HJ, Myers LE, Yen-Lieberman B, et al: Multicenter evaluation of methods for quantitation of plasma HIV-1 RNA. J Infect Dis, in press

        • Lopez-Galindez C.
        • Rojas J.M.
        • Najera R.
        • et al.
        Characterization of genetic variation and AZT resistance mutations of HIV by RNase A mismatch method.
        Proc Natl Acad Sci USA. 1991; 88: 4280-4284
        • Martin J.L.
        • Wilson J.E.
        • Haynes R.L.
        • et al.
        Mechanism of resistance of human immunodeficiency virus type 1 to 2′,3′-dideoxyinosine.
        Proc Natl Acad Sci USA. 1993; 90: 6135-6139
        • Mayers D.
        • McCutchan F.E.
        • Sanders-Buell E.E.
        • et al.
        Characterization of HIV-1 isolates arising after prolonged zidovudine therapy.
        J AIDS. 1992; 5: 749-759
        • Mayers D.L.
        • Japour A.J.
        • Arduino J.M.
        • et al.
        Antimicrob Agents Chemother. 1994; 38: 307-314
      13. Mazzulli T, Rusconi S, Merrill DP, et al: Combination chemotherapy of HIV-1 infection in vitro: Alternating versus continuous drug regimens. Antimicrob Agents Chemother 1994, in press

        • McLeod G.X.
        • McGrath J.M.
        • Ladd E.A.
        • et al.
        Didanosine and zidovudine resistance patterns in clinical isolates of human immunodeficiency virus type 1 as determined by a replication endpoint concentration assay.
        Antimicrob Agents Chemother. 1992; 36: 920-925
        • Mellors J.W.
        • Dutschman G.E.
        • Im G.J.
        • et al.
        In vitro selection and molecular characterization of human immunodeficiency virus-1 resistant to non-nucleoside inhibitors of reverse transcriptase [published erratum appears in Mol Pharmacol 1992 Jul;42(1):174].
        Mol Pharmacol. 1992; 41: 446-451
        • Mellors J.W.
        • Im G.J.
        • Tramontano E.
        • et al.
        A single conservative amino acid substitution in the reverse transcriptase of human immunodeficiency virus-1 confers resistance to (+)-(5S)-4, 5, 6, 7-tetrahydro-5-methyl-6-(3-methyl-2-butenyl)imidazo [4, 5, 1-jk][l,4]benzodiazepin-2(1H)-thione (TIBO R82150).
        Mol Pharmacol. 1993; 43: 11-16
        • Merluzzi V.J.
        • Hargrave K.D.
        • Labadia M.
        • et al.
        Inhibition of HIV-1 replication by a nonnucleoside reverse transcriptase inhibitor.
        Science. 1990; 250: 1411-1413
        • Meyerhans A.
        • Cheynier R.
        • Albert J.
        • et al.
        Temporal fluctuations in HIV quasispecies in vivo are not reflected by sequential HIV isolations.
        Cell. 1989; 58: 901-910
        • Mohri H.
        • Singh M.K.
        • Ching W.T.
        • et al.
        Quantitation of zidovudine-resistant human immunodeficiency virus type 1 in the blood of treated and untreated patients.
        Proc Natl Acad Sci USA. 1993; 90: 25-29
        • Montaner J.S.G.
        • Singer J.
        • Schecter M.T.
        • et al.
        Clinical correlates of in vitro HIV-1 resistance to zidovudine: Results of the Multicentre Canadian AZT Trial.
        AIDS. 1993; 7: 189-196
        • Nunberg J.H.
        • Schleif W.A.
        • Boots E.J.
        • et al.
        Viral resistance to human immunodeficiency virus type 1-specific pyridinone reverse transcriptase inhibitors.
        J Virology. 1991; 65: 4887-4892
        • Ogino M.T.
        • Dankner W.M.
        • Spector S.A.
        Development and significance of zidovudine resistance in children infected with human immunodeficiency virus.
        J Pediatr. 1993; 123: 1-8
        • Otto M.J.
        • Garber S.
        • Winslow D.L.
        • et al.
        In vitro isolation and identification of human immunodeficiency virus (HIV) variants with reduced sensitivity to C-2 symmetrical inhibitors of HIV type 1 protease.
        Proc Natl Acad Sci USA. 1993; 90: 7543-7547
        • Ou C-Y
        • Ciesielski C.A.
        • Myers G.
        • et al.
        Molecular epidemiology of HIV transmission in a dental practice.
        Science. 1992; 256: 1165-1171
        • Pantaleo G.
        • Graziosi C.
        • Deunarest J.F.
        • et al.
        HIV infection is active and progressive in lymphoid tissue during the clinically latent stage of disease.
        Nature. 1993; 362: 355-358
        • Pauwels R.
        • Andries K.
        • Desmyter J.
        • et al.
        Potent and selective inhibition of HIV-1 replication in vitro by a novel series of TIBO derivatives.
        Nature. 1990; 343: 470-474
        • Peliska J.A.
        • Benkovic S.J.
        Mechanism of DNA strand transfer reactions catalyzed by HIV-1 reverse transcriptase.
        Science. 1992; 258: 1112-1118
        • Piatek Jr, M.
        • Saag M.S.
        • Yang L.C.
        • et al.
        High levels of HIV-1 in plasma during all stages of infection determined by competitive PCR.
        Science. 1993; 259: 1749-1754
        • Prasad V.
        • Lowy I.
        • Santos T.D.
        • et al.
        Isolation and characterization of a di-deoxyguanosine triphosphate-resistant mutant of HIV-1 RT.
        Proc Natl Acad Sci USA. 1991; 88: 11363-11367
        • Prasad V.R.
        • Goff S.P.
        A novel in situ colony screening method to detect human immunodeficiency virus reverse transcriptase activity expressed in bacteria: Isolation of pseudorevertants of reverse transcriptase mutants.
        J Biol Chem. 1989; 264: 16689-16693
      14. Reichman R, Lambert J, Strussenberg J, et al: Decreased didanosine (DDI) sensitivity of HIV isolates obtained from long-term recipients of DDI. In VII International Conference on AIDS, Florence, Italy, 1991, p 80

        • Reichman R.C.
        • Tejani N.
        • Lambert J.L.
        • et al.
        Didanosine (ddI) and zidovudine (ZDV) susceptibilities of human immunodeficiency virus (HIV) isolates from long-term recipients of ddI.
        Antiviral Res. 1993; 20: 267-277
      15. Richman D: Interactions of drug resistance mutations of isolates of HIV from patients treated with nevirapine. In Fifth International NCDDG-HIV Conference, Washington, DC, 1993, p 40

      16. Richman D, for the ACTG 164/168 Team: Loss of Nevirapine activity associated with the emergence of resistance in clinical trials [abstract]. In VIII International Conference on AIDS, Amsterdam, The Netherlands, 1992

        • Richman D.
        • Rosenthal A.S.
        • Skoog M.
        • et al.
        BI-RG-587 is active against zidovudineresistant human immunodeficiency virus type 1 and synergistic with zidovudine.
        Antimicrob Agents Chemother. 1991; 35: 305-308
        • Richman D.
        • Shih C.K.
        • Lowy I.
        • et al.
        Human immunodeficiency virus type 1 mutants resistant to non-nucleoside inhibitors of reverse transcriptase arise in tissue culture.
        Proc Natl Acad Sci USA. 1991; 88: 11241-11245
      17. Richman DD, Bozzette SA: The impact of the syncytium-inducing phenotype of human immunodeficiency virus on disease progression. J Infect Dis, in press

        • Richman D.D.
        • Guatelli J.C.
        • Grimes J.
        • et al.
        Detection of mutations associated with zidovudine resistance in human immunodeficiency virus by use of the polymerase chain reaction.
        J Infect Dis. 1991; 164: 1075-1081
      18. Robins T, Vasavanonda S, Blohm S, et al: Isolation and characterization of HIV-1 mutants resistant to HIV-1 protease inhibitors [abstract 267]. In First National Conference on Human Retroviruses and Related Infections, Washington, DC, 1993, p 101

        • Romero D.L.
        • Busso M.
        • Tan C-K
        • et al.
        Nonnucleoside RT inhibitor that potently and specifically blocks HIV-1 replication.
        Proc Natl Acad Sci USA. 1991; 88: 8806-8810
        • Rooke R.
        • Parniak M.A.
        • Tremblay M.
        • et al.
        Biological comparison of wild-type and zidovudine-resistant isolates of human immunodeficiency virus type 1 from the same subjects: Susceptibility and resistance to other drugs.
        Antimicrob Agents Chemother. 1991; 35: 988-991
        • Rooke R.
        • Tremblay M.
        • Soudeyns H.
        Isolation of drug-resistant variants of HIV-1 from patients on long-term zidovudine therapy.
        AIDS. 1989; 3: 411-415
        • Saag M.S.
        • Emini E.A.
        • Laskin O.L.
        • et al.
        A short-term clinical evaluation of L-697, 661, a non-nucleoside inhibitor of HIV-1 reverse transcriptase: L-697, 661 Working Group.
        N Engl J Med. 1993; 329: 1065-1072
        • Sardana V.V.
        • Emini E.A.
        • Gotlib L.
        • et al.
        Functional analysis of HIV-1 reverse transcriptase amino acids involved in resistance to multiple nonnucleoside inhibitors.
        J Biol Chem. 1992; 267: 17526-17530
        • Schinazi R.F.
        • Lloyd R.M.
        • Nguyen M-H
        • et al.
        Characterization of human immunodeficiency viruses resistant to oxathiolane-cytosine nucleosides.
        Antimicrob Agents Chemother. 1993; 37: 875-881
        • Schleif W.A.
        • Emini E.A.
        • Rhodes A.
        • et al.
        Development and analysis of human immunodeficiency virus type 1 resistant to HIV-1 specific pyridinone reverse transcriptase inhibitors.
        J Cell Biochem. 1992; 16E: 87
        • Shafer R.W.
        • Kozal M.J.
        • Winters M.A.
        • et al.
        Combination therapy with zidovudine (AZT) selects for non-syncytia-inducing, AZT resistant HIV-1 strains lacking a ddI-resistance mutation.
        in: Second International HIV Drug-Resistance Workshop. Noordwijk, The Netherlands1993: 48
        • Sheehy N.
        • Desselberger U.
        Sequence analysis of reverse transcriptase genes of zidovudine (AZT)-resistant and -sensitive human immunodeficiency virus type 1 strains.
        J Gen Virol. 1993; 74: 223-228
        • Shih C.K.
        • Rose J.M.
        • Hansen G.L.
        • et al.
        Chimeric human immunodeficiency virus type 1/type 2 reverse transcriptases display reversed sensitivity to nonnucleoside analog inhibitors.
        Proc Natl Acad Sci USA. 1991; 88: 9878-9882
        • Shirasaka T.
        • Yarcjoan R.
        • O’Brien M.C.
        • et al.
        Changes in drug sensitivity of human immunodeficiency virus type 1 during therapy with azidothymidine, dideoxycytidine, and dideoxyinosine: An in vitro comparative study.
        Proc Natl Acad Sci USA. 1993; 90: 562-566
        • Simmonds P.
        • Balfe P.
        • Ludlam C.A.
        • et al.
        Analysis of sequence diversity of the hypervariable regions of the external glycoprotein of human immunodeficiency virus type 1.
        J Virol. 1990; 64: 5840-5850
        • Simmonds P.
        • Zhang L.Q.
        • McOmish F.
        • et al.
        Discontinuous sequence change of HIV-1 env sequences in plasma viral and lymphocyte associated proviral populations in vivo: Implications for models of HIV pathogenesis.
        J Virol. 1991; 65: 6266-6276
        • Smith M.S.
        • Brian E.L.
        • Pagano J.S.
        Resumption of virus production after human immunodeficiency virus infection of T lymphocytes in the presence of azidothymidine.
        J Virol. 1987; 61: 3769-3773
        • Smith M.S.
        • Koerber K.L.
        • Pagano J.S.
        Zidovudine-resistant human immunodeficiency virus type 1 genomes detected in plasma distinct from viral genomes in peripheral blood mononuclear cells.
        J Infect Dis. 1993; 167: 445-448
        • St. Clair M.H.
        • Hartigan P.M.
        • Andres J.C.
        • et al.
        Zidovudine resistance, syncytium-inducing phenotype, and HIV disease progression in a case-control study.
        J AIDS. 1993; 6: 891-897
        • St. Clair M.H.
        • Martin J.L.
        • Tudor-Williams G.
        • et al.
        Resistance to ddI and sensitivity to AZT induced by a mutation in HIV-1 reverse transcriptase.
        Science. 1991; 253: 1557-1559
      19. Strair RK, Medina DJ, Nelson CJ, et al: Use of recombinant human immunodeficiency viruses to quantitate antiretroviral drug resistance. In Third Workshop on Viral Resistance, Gaithersburg, MD, 1993

        • Tisdale M.
        • Kemp S.D.
        • Parry N.R.
        • et al.
        Rapid in vitro selection of human immunodeficiency virus type 1 resistant to 3′-thiacytidine inhibitors due to a mutation in the YMDD region of reverse transcriptase.
        Proc Natl Acad Sci USA. 1993; 90: 5653-5656
        • Tramontano E.
        • Cheng Y.C.
        HIV-1 reverse transcriptase inhibition by a di-pyridodiazepinone derivative: BI-RG-587.
        Biochem Pharmacol. 1992; 43: 1371-1376
        • Tudor-Williams G.
        • St. Clair M.H.
        • McKinney R.E.
        • et al.
        HIV-1 sensitivity to zidovudine and clinical outcome [letter].
        Lancet. 1992; 339: 627
        • Tudor-Williams G.
        • St. Clair M.H.
        • McKinney R.E.
        • et al.
        HIV-1 sensitivity to zidovudine and clinical outcome in children.
        Lancet. 1992; 339: 15-19
        • Vasudevachari M.B.
        • Battista C.
        • Lane H.C.
        • et al.
        Prevention of the spread of HIV-1 infection with nonnucleoside reverse transcriptase inhibitors.
        Virology. 1992; 190: 269-277
        • Wahlberg J.
        • Albert J.
        • Lundeberg J.
        • et al.
        Dynamic changes in HIV-1 quasispecies from azidothymidine (AZT)-treated patients.
        FASEB J. 1992; 6: 2843-2847
        • Wainberg M.A.
        • Arts E.
        • Gu Z.
        • et al.
        Development of viral drug resistance in HIV infection.
        in: Neu H.C. Levy J.A. Weiss R.A. Focus on HIV. Churchill Livingstone, Edinburgh1993
        • Wakefield J.K.
        • Jablonski S.A.
        • Morrow C.D.
        In vitro enzymatic activity of human immunodeficiency virus type 1 reverse transcriptase mutants in the highly conserved YMDD amino acid motif correlates with the infectious potential of the proviral genome.
        J Virol. 1992; 66: 6806-6812
        • Wolfs T.F.
        • Zwart G.
        • Bakker M.
        • et al.
        HIV-1 genomic RNA diversification following sexual and parenteral transmission.
        Virology. 1992; 189: 103-110
        • Wolinsky S.M.
        • Wike C.M.
        • Korber B.T.
        • et al.
        Selective transmission of human immunodeficiency virus type 1 variants from mothers to infants.
        Science. 1992; 255: 1134-1137
      20. Zhang D, Caliendo AM, Eron JJ, et al: Resistance to 2′,3′-dideoxycytidine conferred by a mutation in codon 65 of the human immunodeficiency virus type 1 reverse transcriptase. Antimicrob Agents Chemother 1994, in press

        • Zhang Y-M
        • Dawson S.C.
        • Landsman D.
        • et al.
        Persistence of four related human immunodeficiency virus subtypes during the course of zidovudine therapy: Relationship between virion RNA and proviral DNA.
        J Virol. 1994; 68: 425-432