Establishment ofpredidive method for shift of coreceptor usage in HIV 1-infected individnals

HIV-1感染的疾病进展在很大程度上与HIV-1从CCR 5到CXCR 4的辅助受体使用的转换有关。尽管大多数使用CXCR 4的病毒保留CCR 5的使用，称为R5 X4病毒，但在同时表达CCR 5和CXCR 4的细胞中，R5 X4病毒的复制仅被CXCR 4抑制剂抑制，表明这些病毒优先使用CXCR 4。为了确定Env的哪些区域与CXCR 4的优先使用相关，我们在CXCR 4拮抗剂T140存在下从R5 X4病毒（89.6株）分离了逃逸突变体。一个分离的T140逃逸突变体在gp 120的V3区含有一个单一的氨基酸取代（精氨酸到丝氨酸，R308 S）。用突变体Env假型化荧光素酶报告基因HIV-1表明，在同时表达CCR 5和CXCR 4的细胞感染中，该取代完全赋予了对CXCR 4拮抗剂的抗性，但增加了对CCR 5拮抗剂TAK-779的敏感性，表明优先使用CCR 5。使用表达单个辅助受体的细胞的分析表明，突变体Env主要且有效地利用CCR 5而不是CXCR 4，保留R5 X4表型。这些结果表明，R5 X4病毒对CXCR 4的优先使用是由gp 120的V3区中的单个氨基酸决定的。

The disease progression of HIV-1 infection is largely associated with a switch of coreceptor usage by HIV-1 from CCR5 to CXCR4. Although most of CXCR4-using viruses retain CCR5 usage called R5X4 viruses, the replication of R5X4 viruses were inhibited by CXCR4 inhibitors alone in the cells expressing both CCR5 and CXCR4, indicating the preferential usage of CXCR4 by these viruses. In order to determine which regions of the Env are associated with the preferential usage of CXCR4, we isolated an escape mutant in the presence of a CXCR4 antagonist T140 from an R5X4 virus (89.6 strain). An isolated T140-escape mutant harbored a single amino acid substitution in the V3 region of gp120(Arginine to Serine, R308S). Luciferase-reporter HIV-1 pseudotyped with the mutant Env showed that the substitution totally conferred resistance to CXCR4 antagonists but increased sensitivity to a CCR5 antagonist TAK-779 in the infection of the cells expressing both CCR5 and CXCR4, indicating the preferential usage of CCR5. Analyses using the cells expressing a single coreceptor showed that the mutant Env predominantly and efficiently utilized CCR5 than CXCR4 with retaining R5X4 phenotype. These results indicated that the preferential usage of CXCR4 by the R5X4 virus was determined by the single amino acid in the V3 region of gp120.