Resistance of Human Immunodeficiency Virus Type 1 to a Third-Generation Fusion Inhibitor Requires Multiple Mutations in gp41 and Is Accompanied by a Dramatic Loss of gp41 Function
Resistance of Human Immunodeficiency Virus Type 1 to a Third-Generation Fusion Inhibitor Requires Multiple Mutations in gp41 and Is Accompanied by a Dramatic Loss of gp41 Function
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DOI：
10.1128/jvi.05331-11
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发表时间：
2011-10-01
影响因子：
5.4
通讯作者：
Sanders, Rogier W.
中科院分区：
文献类型：
--
作者：
Eggink, Dirk;Bontjer, Ilja;Sanders, Rogier W.
HIV-1病毒进入靶细胞需要病毒和细胞膜的融合。这一过程是治疗干预的一个有吸引力的靶点，第一代融合抑制剂T20(恩福韦肽；Fuzeon)于2003年被批准用于临床。第二代(T1249)和第三代(T2635)融合抑制剂被开发出来，具有更好的稳定性和效力。对T20和T1249的抗性通常需要结合部位内的一个或两个氨基酸发生变化。我们对T2635的抗性进行了体外进化研究。经过6个月的培养，在所有gp41亚区都发现了大量的耐药突变，但没有一个突变提供有意义的T2635抗性。相比之下，gp41内的多个突变才能产生耐药性，并伴随着病毒感染性的急剧丧失。由于大多数逃逸突变位于T2635结合位点之外，药物靶标亲和力的降低不能解释大部分耐药性。T2635的抗性可能取决于六螺旋束形成动力学的改变，从而限制了T2635干扰膜融合的时间窗口。有趣的是，gp41中T2635耐药突变引起的病毒感染性的丧失可以通过gp120中V3结构域碱基的突变部分补偿。因此，从第三代HIV-1融合抑制剂T2635中逃脱与对其前身T20和T1249的抗性在机制上是不同的。它需要gp41多个突变的积累，伴随着gp41功能的急剧丧失，并诱导gp120的代偿性突变。
HIV-1 entry into target cells requires the fusion of viral and cellular membranes. This process is an attractive target for therapeutic intervention, and a first-generation fusion inhibitor, T20 (Enfuvirtide; Fuzeon), was approved for clinical use in 2003. Second-generation (T1249) and third-generation (T2635) fusion inhibitors with improved stability and potency were developed. Resistance to T20 and T1249 usually requires one or two amino acid changes within the binding site. We studied the in vitro evolution of resistance against T2635. After 6 months of culturing, a multitude of resistance mutations was identified in all gp41 subdomains, but no single mutation provided meaningful T2635 resistance. In contrast, multiple mutations within gp41 were required for resistance, and this was accompanied by a dramatic loss of viral infectivity. Because most of the escape mutations were situated outside the T2635 binding site, a decrease in drug target affinity cannot account for most of the resistance. T2635 resistance is likely to depend on altered kinetics of six-helix bundle formation, thus limiting the time window for T2635 to interfere with membrane fusion. Interestingly, the loss of virus infectivity caused by T2635 resistance mutations in gp41 was partially compensated for by a mutation at the base of the V3 domain in gp120. Thus, escape from the third-generation HIV-1 fusion inhibitor T2635 is mechanistically distinct from resistance against its predecessors T20 and T1249. It requires the accumulation of multiple mutations in gp41, is accompanied with a dramatic loss of gp41 function, and induces compensatory mutations in gp120.