INFECTIVITY OF HSIV-VIF CHIMERA IN NEWBORN PIGTAILED MACAQUES

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 目前，还没有HIV-1感染和疾病的动物模型，因为这种病毒对人类具有高度的特异性。猕猴通常对HIV-1具有抵抗力，但猪尾猕猴除外。我们的实验室发现，猪尾猕猴不能表达TRIM5-α的功能亚型，TRIM5-α被认为是限制HIV-1在恒河猴体内复制的宿主因子。因此，HIV-1可能只需要克服另一个宿主因子APOBEC3G/F的限制，就可以在猪尾猕猴身上成功复制。为了验证这一假设，我们与贝勒医学院的J.Kimata博士合作，他设计了一个HIV-1克隆，其中包括SIVmne的vif基因，使其能够抵消APOBEC3G/F介导的限制。这种嵌合病毒，HSIV-VIF，96%是HIV-1，4%是SIV。它在刺激的猪尾猕猴血细胞中复制的效率与SIVmne一样高。在另一项初步研究中，我们将HSIV-vif静脉接种给2只幼年猪尾猕猴。尽管两只动物都被感染了，但血浆病毒血症在感染后10个月内不会持续。由于新生动物对慢病毒感染和疾病更敏感，我们用HSIV-vif接种了两只新生的猪尾猕猴。两只动物均被感染，血浆病毒载量峰值为0.5-1x105拷贝/毫升。虽然在急性期感染后病毒载量降至基线(100拷贝/毫升)，但在第28周至44周，两只动物的病毒载量都有所回升，表明持续感染。比较研究使我们能够确定嗜铂HIV-1和SIVmne之间的两个显著区别：(1)SIV Vif不与嗜铂HIV-1病毒颗粒相关联；(2)虽然嗜铂HIV-1同时降解PtAPOBEC3G和APOBEC3F，但它阻止它们被病毒粒子包括的程度低于致病SIVmne。因此，尽管SIV Vif对于嗜铂HIV-1的持续感染是必要的，但为了在体内强劲地复制病毒，可能需要改善APOBEC3蛋白的表达和抑制。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Currently, there is no animal model for HIV-1 infection and disease because the virus is highly specific for humans. Macaques are generally resistant to HIV-1, with the exception being pig-tailed macaques. Our lab showed that pig-tailed macaques are unable to express functional isoforms of TRIM5-alpha, which has been identified as a host factor that restricts the replication of HIV-1 in rhesus monkeys. Therefore, it is possible that HIV-1 will only need to overcome restriction by another host factor, APOBEC3G/F, to replicate successfully in pig-tailed macaques. To test this hypothesis, we collaborated with Dr. J. Kimata of Baylor College of Medicine, who engineered an HIV-1 clone that includes the vif gene of SIVmne, allowing it to counteract APOBEC3G/F-mediated restriction. This chimeric virus, HSIV-vif, is 96% HIV-1 and 4% SIV. It replicates in stimulated pig-tailed macaque blood cells as efficiently as SIVmne. In another pilot study, we inoculated 2 juvenile pig-tailed macaques intravenously with HSIV-vif. Although both animals became infected, plasma viremia did not sustain beyond 10 months after infection. Since newborn animals are more susceptible to lentiviral infection and disease, we inoculated two newborn pig-tail macaques with HSIV-vif. Both animals were infected, with a peak plasma viral load of 0.5-1x105 copies/ml. Although viral load decreased to baseline (100 copies/ml) after acute phase infection, it rebounded in both animals between week 28 and 44, indicating persistent infection. Comparative studies allowed us to identified two notable differences between the Pt-tropic HIV-1 and SIVmne (1) SIV Vif does not associate with Pt-tropic HIV-1 viral particles; (2) while Pt-tropic HIV-1 degrades both Pt APOBEC3G and APOBEC3F, it prevents their inclusion in virions to a lesser extent than pathogenic SIVmne. Thus, while SIV Vif is necessary for persistent infection by Pt-tropic HIV-1, improved expression and inhibition of APOBEC3 proteins may be required for robust viral replication in vivo.