Reduced maximal inhibition in phenotypic susceptibility assays indicates that viral strains resistant to the CCR5 antagonist maraviroc utilize inhibitor-bound receptor for entry
Reduced maximal inhibition in phenotypic susceptibility assays indicates that viral strains resistant to the CCR5 antagonist maraviroc utilize inhibitor-bound receptor for entry
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DOI：
10.1128/jvi.02006-06
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发表时间：
2007-03-01
影响因子：
5.4
通讯作者：
Perros, Manos
中科院分区：
文献类型：
--
作者：
Westby, Mike;Smith-Burchnell, Caroline;Perros, Manos
Maraviroc是一种临床开发的CCR5拮抗剂，是一种针对人类免疫缺陷病毒1型（HIV-1）辅助受体结合的新型抗逆转录病毒药物。我们通过体外序列传代和定点诱变研究了HIV对马拉韦洛克的耐药性机制。通过增加马拉韦洛克浓度的连续传代未能从一些实验室适应的HIV-1和临床分离株中选择马拉韦洛克耐药变体。然而，从6株经外周血淋巴细胞传代（PBL）的原代分离株中筛选出3株对马拉韦洛克具有高水平耐药性。SF162菌株在处理和对照培养中均获得了对马拉韦洛克的抗性；所有耐药变体都能够使用CXCR4作为辅助受体。相比之下，从分离物CC1/85和RU570衍生的马拉韦洛克耐药病毒对CCR5拮抗剂schc敏感，对CXCR4拮抗剂AMD3100耐药，并且在马拉韦洛克耐药的CC1/85和RU570的V3环中鉴定出无法复制CCR5 Delta 32/Delta 32 PBL株特异性突变。将抗马拉韦洛克CC1/85的包膜编码区插入NL4-3背景。该重组病毒对马拉韦洛克完全耐药，但对阿普罗维洛克保持敏感性。将gp120 V3环中的316和323残基（从HXB2开始编号）反向突变为原始序列，恢复野生型对马拉韦洛克的易感性，而任何一种突变的逆转都导致部分敏感的病毒减少了最大抑制（平台）。高原期与病毒已获得利用马拉维克结合受体进入的能力相一致。这一假设进一步得到了观察结果的证实，即高浓度的马拉威洛克阻断了阿普aviroc对马拉威洛克耐药病毒的活性。
Maraviroc is a CCR5 antagonist in clinical development as one of a new class of antiretrovirals targeting human immunodeficiency virus type 1 (HIV-1) coreceptor binding. We investigated the mechanism of HIV resistance to maraviroc by using in vitro sequential passage and site-directed mutagenesis. Serial passage through increasing maraviroc concentrations failed to select maraviroc-resistant variants from some laboratory-adapted and clinical isolates of HIV-1. However, high-level resistance to maraviroc was selected from three of six primary isolates passaged in peripheral blood lymphocytes (PBL). The SF162 strain acquired resistance to maraviroc in both treated and control cultures; all resistant variants were able to use CXCR4 as a coreceptor. In contrast, maraviroc-resistant virus derived from isolates CC1/85 and RU570 remained CCR5 tropic, as evidenced by susceptibility to the CCR5 antagonist SCH-C, resistance to the CXCR4 antagonist AMD3100, and an inability to replicate in CCR5 Delta 32/Delta 32 PBL Strain-specific mutations were identified in the V3 loop of maraviroc-resistant CC1/85 and RU570. The envelope-encoding region of maraviroc-resistant CC1/85 was inserted into an NL4-3 background. This recombinant virus was completely resistant to maraviroc but retained susceptibility to aplaviroc. Reverse mutation of gp120 residues 316 and 323 in the V3 loop (numbering from HXB2) to their original sequence restored wild-type susceptibility to maraviroc, while reversion of either mutation resulted in a partially sensitive virus with reduced maximal inhibition (plateau). The plateaus are consistent with the virus having acquired the ability to utilize maraviroc-bound receptor for entry. This hypothesis was further corroborated by the observation that a high concentration of maraviroc blocks the activity of aplaviroc against maraviroc-resistant virus.