Winters M A, Shafer R W, Jellinger R A, Mamtora G, Gingeras T, Merigan T C
Center for AIDS Research, Stanford University, California, USA.
Antimicrob Agents Chemother. 1997 Apr;41(4):757-62. doi: 10.1128/AAC.41.4.757.
The genetic mechanisms of human immunodeficiency virus type 1 (HIV-1) resistance to dideoxyinosine (ddI) in vivo have been described based on data from primary HIV-1 isolates. To better define the spectrum of HIV-1 reverse transcriptase (RT) changes occurring during ddI therapy, we determined the genotype and ddI susceptibility of the RT gene of HIV RNA isolated from the plasma of 23 patients who had received 1 to 2 years (mean, 87 +/- 16 weeks) of ddI monotherapy. Population-based sequencing of plasma virus showed that 12 of 23 (52%) patients developed known ddI resistance mutations: L74V (7 patients), K65R (2 patients), L74V with M184V (3 patients), and L74V with K65R (1 patient). Five patients developed one or more known zidovudine resistance mutations (at codons 41, 67, 70, 215, and/or 219) during the study. Other amino acid substitutions were found, but only S68G and L210W occurred in more than one patient. Studies of sensitivity to ddI were performed on population-based recombinant-virus stocks generated by homologous recombination between a plasmid containing an HXB2 clone with the RT gene deleted and RT-PCR products of the RT genes from patients' plasma RNA. The sequences of the virus stocks produced by this procedure were typically identical to the sequence of the input PCR product from plasma RNA. Both an MT-2 cell-based culture assay and a cell-free virion-associated RT inhibition assay showed that viruses possessing an L74V and/or M184V mutation or a K65R mutation had reduced sensitivity to ddI. Viruses without these specific mutations had no change in sensitivity to ddI. The results presented here show that the spectrum of RT mutations in a population of patients on ddI monotherapy is more complex than previously described. The development of multiple mutational patterns, including those that confer resistance to other nucleoside analogs, highlights the complexity of using the currently available nucleoside analogs for antiretroviral therapy.
基于来自原发性人类免疫缺陷病毒1型（HIV-1）分离株的数据，已经描述了HIV-1在体内对双脱氧肌苷（ddI）耐药的遗传机制。为了更好地确定在ddI治疗期间发生的HIV-1逆转录酶（RT）变化范围，我们测定了从23名接受了1至2年（平均87±16周）ddI单药治疗患者的血浆中分离的HIV RNA的RT基因的基因型和对ddI的敏感性。基于群体的血浆病毒测序显示，23名患者中有12名（52%）出现了已知的ddI耐药突变：L74V（7名患者）、K65R（2名患者）、L74V与M184V同时出现（3名患者）以及L74V与K65R同时出现（1名患者）。在研究期间，5名患者出现了一个或多个已知的齐多夫定耐药突变（位于密码子41、67、70、215和/或219）。还发现了其他氨基酸替代，但只有S68G和L210W在不止一名患者中出现。对基于群体的重组病毒株进行了对ddI的敏感性研究，这些重组病毒株是通过在一个含有缺失RT基因的HXB2克隆的质粒与患者血浆RNA的RT基因的RT-PCR产物之间进行同源重组产生的。通过该程序产生的病毒株序列通常与来自血浆RNA的输入PCR产物的序列相同。基于MT-2细胞的培养试验和无细胞病毒体相关的RT抑制试验均表明，具有L74V和/或M184V突变或K65R突变的病毒对ddI的敏感性降低。没有这些特定突变的病毒对ddI的敏感性没有变化。此处呈现的结果表明，接受ddI单药治疗的患者群体中RT突变的范围比先前描述的更为复杂。多种突变模式的出现，包括那些赋予对其他核苷类似物耐药性的模式，凸显了使用目前可用的核苷类似物进行抗逆转录病毒治疗的复杂性。
