Luciw P A, Mandell C P, Himathongkham S, Li J, Low T A, Schmidt K A, Shaw K E, Cheng-Mayer C
Department of Medical Pathology, University of California, Davis, California 95616, USA.
Virology. 1999 Oct 10;263(1):112-27. doi: 10.1006/viro.1999.9908.
SIV/HIV-1 (SHIV) chimeric clones, constructed by substituting portions of the pathogenic molecular clone SIVmac239 with counterpart portions from HIV-1 clones, provide a means to analyze functions of selected HIV-1 genes in vivo in nonhuman primates. Our studies focused on SHIVSF33, which contains the vpu, tat, rev, and env genes of the cytopathic, T-cell line tropic clone HIV-1sf33 (subtype-B); this clone has a premature stop codon in the vpu gene. In three juvenile macaques inoculated intravenously with SHIVSF33, low-level persistent infection was established; no disease was observed for a period of >2 years. However, at approximately 16 months p.i., one of four SHIVSF33-infected juvenile macaques exhibited an increase in virus load, depletion of CD4(+) T cells in peripheral blood and lymph nodes, and other symptoms of simian AIDS (SAIDS). Virus recovered from this animal in the symptomatic stage was designated SHIVSF33a (A, adapted); this virus displayed multiple amino acid sequence changes throughout the HIV-1 env gene compared with the input SHIVSF33 clone. Additionally, a mutation in all clones from SHIVSF33a restored the open reading frame for the vpu gene. In vitro evaluations in tissue-culture systems revealed that SHIVSF33a replicated to higher levels and exhibited greater cytopathicity than SHIVSF33. Furthermore cloned env genes for SHIVSF33a were more fusogenic in a cell-fusion assay compared with the env gene of the SHIVSF33. Intravenous inoculation of SHIVsf33a into juvenile and newborn macaques resulted in a rapid decline in CD4(+) T cells to very low levels and development of a fatal AIDS-like disease. A cell-free preparation of this pathogenic chimeric virus also established persistent infection when applied to oral mucosal membranes of juvenile macaques and produced a fatal AIDS-like disease. These studies on pathogenic SHIVSF33a establish the basis for further investigations on the role of the HIV-1 env gene in virus adaptation and in mechanism(s) of immunodeficiency in primates; moreover, the chimeric virus SHIVSF33a can play a role in elucidating mucosal membrane transmission and development of antiviral vaccines in newborns as well as juvenile and adult macaques.
通过用HIV-1克隆的对应部分替换致病性分子克隆SIVmac239的部分构建的SIV/HIV-1（SHIV）嵌合克隆，为在非人灵长类动物体内分析选定HIV-1基因的功能提供了一种手段。我们的研究集中在SHIVSF33上，它包含细胞病变性、T细胞系嗜性克隆HIV-1sf33（B亚型）的vpu、tat、rev和env基因；该克隆在vpu基因中有一个提前的终止密码子。在三只静脉接种SHIVSF33的幼年猕猴中，建立了低水平的持续感染；在超过2年的时间里未观察到疾病。然而，在感染后约16个月时，四只感染SHIVSF33的幼年猕猴中有一只病毒载量增加，外周血和淋巴结中的CD4(+)T细胞耗竭，以及出现其他猴艾滋病（SAIDS）症状。从这只处于有症状阶段的动物中分离出的病毒被命名为SHIVSF33a（A，适应性）；与输入的SHIVSF33克隆相比，这种病毒在整个HIV-1 env基因中显示出多个氨基酸序列变化。此外，来自SHIVSF33a的所有克隆中的一个突变恢复了vpu基因的开放阅读框。在组织培养系统中的体外评估显示，SHIVSF33a的复制水平更高，并且比SHIVSF33表现出更大的细胞病变性。此外，与SHIVSF33的env基因相比，SHIVSF33a的克隆env基因在细胞融合试验中更具融合性。将SHIVsf33a静脉接种到幼年和新生猕猴中导致CD4(+)T细胞迅速下降到非常低的水平，并发展出致命的艾滋病样疾病。当将这种致病性嵌合病毒的无细胞制剂应用于幼年猕猴的口腔黏膜时，也建立了持续感染，并产生了致命的艾滋病样疾病。这些关于致病性SHIVSF33a的研究为进一步研究HIV-1 env基因在病毒适应性和灵长类动物免疫缺陷机制中的作用奠定了基础；此外，嵌合病毒SHIVSF33a在阐明新生儿以及幼年和成年猕猴的黏膜传播和抗病毒疫苗开发方面可以发挥作用。
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