Section of Retroviral Therapeutics, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
J Acquir Immune Defic Syndr. 2010 Oct;55(2):148-55. doi: 10.1097/QAI.0b013e3181e9a87a.
Raltegravir resistance is conferred by mutations at integrase codons 143, 148, and 155 together with associated secondary mutations. The N155H mutants emerge first, and are eventually replaced by Q148H mutants, usually in combination with G140S. These mutations have different effects on susceptibility and replication capacity, but data on the relative fitness of RAL-resistant viruses are limited. To understand the impact of the different RAL resistance pathways on viral fitness, mutations at integrase codons 74, 92, 138, 140, 148, 155, and/or 163 were introduced into HIV-1NL4-3 by site-directed mutagenesis and expressed in recombinant viruses. Relative fitness and drug susceptibility were determined in the absence or presence of RAL. In the absence of drug, RAL-resistant mutants were less fit than wild type, and the Q148H mutant was significantly less fit than the N155H mutant. Fitness was partially restored by the presence of additional RAL resistance mutations at positions G140S and E92Q or E138K, respectively. In the presence of RAL, the N155H mutant remained fitter than the Q148H mutant, but the G140S/Q148H double mutant was fitter than single mutants or the E92Q/N155H double mutant. These findings correspond well with the clinical trials data and help explain the temporal pattern of RAL resistance evolution.
整合酶密码子 143、148 和 155 处的突变以及相关的次要突变赋予拉替拉韦耐药性。首先出现 N155H 突变体，最终被 Q148H 突变体取代，通常与 G140S 一起。这些突变对敏感性和复制能力有不同的影响，但关于 RAL 耐药病毒相对适应性的数据有限。为了了解不同 RAL 耐药途径对病毒适应性的影响，通过定点诱变将整合酶密码子 74、92、138、140、148、155 和/或 163 的突变引入 HIV-1NL4-3 中，并在重组病毒中表达。在没有或存在 RAL 的情况下，确定相对适应性和药物敏感性。在没有药物的情况下，RAL 耐药突变体的适应性比野生型差，而 Q148H 突变体的适应性明显比 N155H 突变体差。通过在位置 G140S 和 E92Q 或 E138K 处分别存在其他 RAL 耐药突变，适应性得到部分恢复。在存在 RAL 的情况下，N155H 突变体仍然比 Q148H 突变体更适应，但 G140S/Q148H 双突变体比单突变体或 E92Q/N155H 双突变体更适应。这些发现与临床试验数据非常吻合，有助于解释 RAL 耐药性演变的时间模式。
