Monogram Biosciences, South San Francisco, California, USA.
AIDS. 2010 Sep 10;24(14):2181-6. doi: 10.1097/QAD.0b013e32833c543f.
OBJECTIVE(S): Dual HIV-1 utilizes cellular CCR5 and CXCR4 coreceptors to enter host cells. Recent studies indicate that the ability of these viruses to use both coreceptors varies significantly in cell lines expressing CXCR4 or CCR5; however, it is not clear whether differences in coreceptor mediated infection in vitro reflect infection of primary cells in vivo.
We evaluated coreceptor usage of dual envelope clones from patient viruses using a single-cycle pseudovirus assay conducted in cell lines and a replication-competent assay performed using peripheral blood mononuclear cells. Dual envelope clones were selected and classified into three groups, R5>X4, R5 approximately X4, and X4>R5, based on their ability to mediate entry by using CXCR4 and CCR5 in a pseudovirus assay.
We observed a high degree of concordance between measurements of coreceptor-mediated entry in pseudovirus and peripheral blood mononuclear cell assays. R5>X4 viruses were efficiently inhibited by a CCR5 antagonist, but not a CXCR4 antagonist, whereas X4>R5 viruses were efficiently inhibited by a CXCR4 antagonist, but not a CCR5 antagonist. R5 approximately X4 viruses were not inhibited, or only partially inhibited, by either a CCR5 or a CXCR4 antagonist alone.
These observations indicate that measurements of coreceptor use determined using pseudoviruses and coreceptor-expressing cell lines are generally concordant with the results obtained using replication-competent assays and peripheral blood mononuclear cell. This suggests that a considerable fraction of dual viruses preferentially infect either CCR5 or CXCR4 target cells in vivo. The clinical implications of preferential coreceptor utilization by dual viruses, that is, HIV-1 pathogenesis and response to coreceptor antagonists, require additional studies.
双重 HIV-1 利用细胞 CCR5 和 CXCR4 核心受体进入宿主细胞。最近的研究表明，这些病毒使用这两种核心受体的能力在表达 CXCR4 或 CCR5 的细胞系中差异很大；然而，尚不清楚体外核心受体介导的感染差异是否反映了体内原代细胞的感染。
我们使用细胞系中的单循环假病毒测定法和使用外周血单核细胞进行的复制能力测定法，评估了来自患者病毒的双重包膜克隆的核心受体使用情况。根据在假病毒测定中使用 CXCR4 和 CCR5 介导进入的能力，将双重包膜克隆选择并分类为 R5>X4、R5 约 X4 和 X4>R5 三组。
我们观察到在假病毒和外周血单核细胞测定中核心受体介导进入的测量之间具有高度一致性。R5>X4 病毒被 CCR5 拮抗剂有效抑制，但不被 CXCR4 拮抗剂抑制，而 X4>R5 病毒被 CXCR4 拮抗剂有效抑制，但不被 CCR5 拮抗剂抑制。R5 约 X4 病毒不受 CCR5 或 CXCR4 拮抗剂的单独抑制，或者仅部分抑制。
这些观察结果表明，使用假病毒和表达核心受体的细胞系测定的核心受体使用测量通常与使用复制能力测定法和外周血单核细胞获得的结果一致。这表明双重病毒中有相当一部分优先感染体内的 CCR5 或 CXCR4 靶细胞。双重病毒对核心受体的优先利用的临床意义，即 HIV-1 发病机制和对核心受体拮抗剂的反应，需要进一步研究。
