Gonzalez Luis M F, Santos André F, Abecasis Ana B, Van Laethem Kristel, Soares Esmeralda A, Deforche Koen, Tanuri Amilcar, Camacho Ricardo, Vandamme Anne-Mieke, Soares Marcelo A
Departamento de Genética, Universidade Federal do Rio de Janeiro, CCS-Bloco A, sala A2-120, Cidade Universitária-Ilha do Fundão, Rio de Janeiro RJ 21949-970, Brazil.
J Antimicrob Chemother. 2008 Jun;61(6):1201-4. doi: 10.1093/jac/dkn099. Epub 2008 Mar 20.
Non-B human immunodeficiency virus (HIV)-1 subtypes possess several amino acid signatures in the viral protease that distinguish them from subtype B, some of which are reported as secondary drug-related mutations. We have previously shown a strong statistical interdependency of residues 71, 89 and 90 in subtype G, but the impact of substitutions on protease inhibitor (PI) resistance is unknown.
We selected subtype G viruses from patients with diverse amino acid combinations at codons 71 (A/T), 74 (T/S), 89 (I/L/M/V) and 90 (L/M). Viral protease genes were inserted into an HIV molecular clone (HXB2). PI drug susceptibilities of chimeric viruses were determined.
In isolates displaying 89I/V in combination with A71 or T74, a reversal to subtype G wild-type 89M was observed after growth in the absence of PI. The presence of 71T in one isolate and 74S in another allowed the persistence of 89I. Mutation 90M conferred intermediate but significant degrees of drug resistance to ritonavir and nelfinavir in subtype G viruses. The combination of 71T or 74S, 89I and 90M resulted in higher levels of resistance to those PIs.
Our results point to the hypothesis that 71T or 74S stabilizes 89I in the protease of subtype G, whose association was previously seen by Bayesian network analyses. The association of 89I with 90M may further increase the PI resistance of subtype G viruses when compared with 90M alone, highlighting novel mutational profiles for drug resistance in this non-B subtype.
非B型人类免疫缺陷病毒（HIV）-1亚型在病毒蛋白酶中具有多个氨基酸特征，使其与B型亚型区分开来，其中一些特征被报道为与药物相关的继发突变。我们之前已经证明G型亚型中71、89和90位残基之间存在很强的统计相关性，但这些取代对蛋白酶抑制剂（PI）耐药性的影响尚不清楚。
我们从密码子71（A/T）、74（T/S）、89（I/L/M/V）和90（L/M）具有不同氨基酸组合的患者中选择G型亚型病毒。将病毒蛋白酶基因插入HIV分子克隆（HXB2）中。测定嵌合病毒对PI药物的敏感性。
在显示89I/V与A71或T74组合的分离株中，在无PI的情况下生长后，观察到向G型亚型野生型89M的逆转。一个分离株中存在71T，另一个分离株中存在74S，使得89I得以持续存在。90M突变使G型亚型病毒对利托那韦和奈非那韦产生中度但显著程度的耐药性。71T或74S、89I和90M的组合导致对这些PI的耐药性更高。
我们的结果指向这样一个假设，即71T或74S在G型亚型蛋白酶中稳定89I，之前通过贝叶斯网络分析观察到了它们的关联。与单独的90M相比，89I与90M的关联可能会进一步增加G型亚型病毒对PI的耐药性，突出了这种非B型亚型中耐药性的新突变谱。
