Sugimoto Chie, Tadakuma Kei, Otani Isao, Moritoyo Takashi, Akari Hirofumi, Ono Fumiko, Yoshikawa Yasuhiro, Sata Tetsutaro, Izumo Shuji, Mori Kazuyasu
Tsukuba Primate Center for Medical Sciences, National Institute of Infectious Diseases, Tsukuba, Japan.
J Virol. 2003 Apr;77(7):4169-80. doi: 10.1128/jvi.77.7.4169-4180.2003.
The pathogenesis of AIDS virus infection in a nonhuman primate AIDS model was studied by comparing plasma viral loads, CD4(+) T-cell subpopulations in peripheral blood mononuclear cells, and simian immunodeficiency virus (SIV) infection in lymph nodes for rhesus macaques infected with a pathogenic molecularly cloned SIVmac239 strain and those infected with its nef deletion mutant (Deltanef). In agreement with many reports, whereas SIVmac239 infection induced AIDS and depletion of memory CD4(+) T cells in 2 to 3 years postinfection (p.i.), Deltanef infection did not induce any manifestation associated with AIDS up to 6.5 years p.i. To explore the difference in SIV infection in lymphoid tissues, we biopsied lymph nodes at 2, 8, 72, and 82 weeks p.i. and analyzed them by pathological techniques. Maximal numbers of SIV-infected cells (SIV Gag(+), Env(+), and RNA(+)) were detected at 2 weeks p.i. in both the SIVmac239-infected animals and the Deltanef-infected animals. In the SIVmac239-infected animals, most of the infected cells were localized in the T-cell-rich paracortex, whereas in the Deltanef-infected animals, most were localized in B-cell-rich follicles and in the border region between the paracortex and the follicles. Analyses by double staining of CD68(+) macrophages and SIV Gag(+) cells and by double staining of CD3(+) T cells and SIV Env(+) cells revealed that SIV-infected cells were identified as CD4(+) T cells in either the SIVmac239 or the Deltanef infection. Whereas the many functions of Nef protein were reported from in vitro studies, our finding of SIVmac239 replication in the T-cell-rich paracortex in the lymph nodes supports the reported roles of Nef protein in T-cell activation and enhancement of viral infectivity. Furthermore, the abundance of SIVmac239 infection and the paucity of Deltanef infection in the T-cell-rich paracortex accounted for the differences in viral replication and pathogenicity between SIVmac239 and the Deltanef mutant. Thus, our in vivo study indicated that the nef gene enhances SIV replication by robust productive infection in memory CD4(+) T cells in the T-cell-rich region in lymphoid tissues.
通过比较感染致病性分子克隆的SIVmac239毒株的恒河猴和感染其nef缺失突变体（Deltanef）的恒河猴的血浆病毒载量、外周血单核细胞中的CD4(+) T细胞亚群以及淋巴结中的猴免疫缺陷病毒（SIV）感染情况，研究了非人类灵长类动物艾滋病模型中艾滋病病毒感染的发病机制。与许多报道一致，SIVmac239感染在感染后（p.i.）2至3年诱发艾滋病并导致记忆CD4(+) T细胞耗竭，而Deltanef感染在感染后长达6.5年未诱发任何与艾滋病相关的表现。为了探究淋巴组织中SIV感染的差异，我们在感染后2、8、72和82周对淋巴结进行活检，并通过病理技术进行分析。在感染后2周，在SIVmac239感染的动物和Deltanef感染的动物中均检测到最大数量的SIV感染细胞（SIV Gag(+)、Env(+)和RNA(+)）。在SIVmac239感染的动物中，大多数感染细胞位于富含T细胞的副皮质区，而在Deltanef感染的动物中，大多数位于富含B细胞的滤泡以及副皮质区和滤泡之间的边界区域。通过CD68(+)巨噬细胞和SIV Gag(+)细胞的双重染色以及CD3(+) T细胞和SIV Env(+)细胞的双重染色分析表明，在SIVmac239或Deltanef感染中，SIV感染细胞均被鉴定为CD4(+) T细胞。尽管体外研究报道了Nef蛋白的许多功能，但我们发现SIVmac239在淋巴结中富含T细胞的副皮质区复制，这支持了Nef蛋白在T细胞活化和增强病毒感染性方面的报道作用。此外，SIVmac239在富含T细胞的副皮质区的大量感染以及Deltanef在该区域的少量感染解释了SIVmac239与Deltanef突变体之间病毒复制和致病性的差异。因此，我们的体内研究表明，nef基因通过在淋巴组织中富含T细胞区域的记忆CD4(+) T细胞中进行强大的有效感染来增强SIV复制。
