Wei Qing, Fultz Patricia N
Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, USA.
J Virol. 2002 Jan;76(2):851-64. doi: 10.1128/jvi.76.2.851-864.2002.
Regardless of the route of transmission, it is generally accepted that the human immunodeficiency virus type 1 (HIV-1) quasispecies transmitted from an infected individual to an uninfected individual is genetically homogeneous. This finding and the observation that HIV-1 genotypes in recipients are minor variants in the donors suggest strongly that selection for specific variants occurs. However, most analyses have been limited to the V3 region of env. In addition, the exact time at which most new infections occurred was not known, making it almost impossible to analyze virus populations present in donor-recipient pairs at the time of HIV-1 transmission. To circumvent this problem, three chimpanzees were inoculated with a genetically defined stock of cell-free HIV-1/JC499 by one of three routes: intravenously or via the cervical or penile mucosa. PCR products of the C2-to-V5 region of env were amplified from both proviral DNA and virion RNA in blood samples collected soon after infection and were screened by heteroduplex analysis (HDA). Those PCR products with distinct HDA banding patterns were cloned and sequenced. In all three animals, transmitted variants encoded one of two V3-loop populations identified in the inoculum, indicating relative homogeneity in this region. However, different virus populations, defined by combinations of specific V4 and V5 sequences, were found when variants in the animal inoculated intravenously (at least 13 V4-plus-V5 combinations) were compared with those in the two animals inoculated by the mucosal routes (limited to only four V4-plus-V5 combinations). The only V4-plus-V5 population in variants found in all three chimpanzees was the major population in the inoculum, which contained viruses with more than 30 different V4-plus-V5 combinations. That the majority of the V4-plus-V5 genotypes in variants transmitted to all three animals were minor populations in the inoculum indicated that selective transmission defined by the V4-plus-V5 regions had occurred but that distinct populations were transmitted by parenteral versus mucosal routes. These results indicate that the putative homogeneity of HIV-1 variants in a newly infected individual might be an artifact of the region of the env gene evaluated and that regions other than V3 might play a major role in selective transmission.
无论传播途径如何，人们普遍认为，从感染个体传播到未感染个体的1型人类免疫缺陷病毒（HIV-1）准种在基因上是同质的。这一发现以及受者体内的HIV-1基因型是供者体内的次要变体这一观察结果强烈表明，特定变体的选择是存在的。然而，大多数分析仅限于env基因的V3区域。此外，大多数新感染发生的确切时间并不清楚，这使得几乎不可能分析HIV-1传播时供者-受者对中存在的病毒群体。为了解决这个问题，三只黑猩猩通过三种途径之一接种了基因明确的无细胞HIV-1/JC499毒株：静脉内接种或通过宫颈或阴茎黏膜接种。在感染后不久采集的血液样本中，从原病毒DNA和病毒体RNA中扩增env基因C2至V5区域的PCR产物，并通过异源双链分析（HDA）进行筛选。那些具有独特HDA条带模式的PCR产物被克隆并测序。在所有三只动物中，传播的变体编码接种物中鉴定出的两种V3环群体之一，表明该区域具有相对同质性。然而，当将静脉内接种的动物（至少13种V4加V5组合）中的变体与通过黏膜途径接种的两只动物（仅限于四种V4加V5组合）中的变体进行比较时，发现了由特定V4和V5序列组合定义的不同病毒群体。在所有三只黑猩猩中发现的变体中唯一的V(4+)V(5)群体是接种物中的主要群体，其中包含具有30多种不同V(4+)V(5)组合的病毒。传播到所有三只动物的变体中，大多数V(4+)V(5)基因型在接种物中是次要群体，这表明由V(4+)V(5)区域定义的选择性传播已经发生，但不同群体是通过肠外途径与黏膜途径传播的。这些结果表明，新感染个体中HIV-1变体的假定同质性可能是所评估的env基因区域的人为现象，并且V3以外的区域可能在选择性传播中起主要作用。
