Inhibition of HIV-1 expression by HIV-2

HIV-1 and HIV-2 are co-endemic in certain geographic areas. HIV-2 is more weakly pathogenic than HIV-1, and progression to AIDS occurs less frequently and over a longer period of time. Recent epidemiologic studies suggest that individuals infected with HIV-2 have a lower risk of HIV-1 infection. Both immune mechanisms and various modes of viral interference have been proposed to account for these results. Our findings, described in this paper, suggest that HIV-2 inhibits HIV-1 replication. To study the molecular interactions between HIV-1 and HIV-2, proviral clones were transfected alone or in combination into the human T cell line CEM. LTR-CAT indicator constructs were included for the purpose of monitoring viral promoter activity. Viral replication in transfected cells was monitored by p24 antigen capture assay of cell culture supernatants and Western blot analysis of cell extracts. HIV-2 inhibited HIV-1 replication as determined by intracellular and extracellular p24 antigen levels. Similar results were obtained with simultaneous virus infection using HIV-1 and HIV-2, rather than transfections of proviral DNA. Using cotransfection of HIV-1 and HIV-2 LTR indicator gene constructs, the mechanism of inhibition was found to be suppression of the HIV-1 LTR by HIV-2. The inhibitory effect of HIV-2 is not due to Tat-2, but appears to discriminate between the HIV-1 and HIV-2 LTRs based on differences in the Tat activation response element, TAR. These results suggest both a molecular mechanism for HIV-2 interference with HIV-1 replication and a potential molecular approach to therapy.     

Preparation and evaluation of the 1st international standard for the quantitation of HIV-2 RNA in plasma

An international standard for the quantitation of HIV-2 RNA in plasma samples was developed. A collaborative study involving 29 laboratories from 15 countries was carried out in order to evaluate HIV-2 RNA candidate materials for use with nucleic acid-based tests (NATs). Candidate reference standards consisted of duplicate copies of two HIV-2 genotype A viruses, HIV-2 CAM2 and HIV-2 ROD and were coded S1-S4. Each laboratory assayed all four candidates on at least three separate occasions and data were collated and analysed at NIBSC. Of the data sets returned the majority were from qualitative assays. All assays detected both candidate standards with the exception of one commercial assay, the Nuclisens Easy Q, which was designed primarily for HIV-1 detection which did not detect HIV-2 CAM2 but showed good detection of HIV-2 ROD. This highlighted possible cross reactivity with HIV-2 ROD with some NAT primer/probe combinations; as a result the HIV-2 CAM2 material was established as the 1st international standard for HIV-2 RNA with an assigned unitage of 1000 International Units (IU) per ampoule and is available upon request from the National Institute for Biological Standardisation and Control (NIBSC) (www.nibsc.ac.uk).     

RNA干扰抑制小鼠脾淋巴细胞分泌IL-1α

目的：确定针对IL-1α的siRNA在细胞内与其具有同源互补序列的靶标位点结合后，特异性降解IL-1α的mRNA，从而抑制其表达的效果。方法:体外PCR扩增合成针对IL-1α靶位点的DNA表达盒，纯化后转染经LPS激活的小鼠脾淋巴细胞，在细胞内源性RNA聚合酶Ⅲ作用下转录形成siRNA，诱发目标mRNA的降解。于转染后 48 h 收集细胞培养上清。用ELISA法测定IL-1α浓度。结果:干扰组IL-1α分泌量明显低于对照组和无关干扰组（P<0.05），抑制率约为15%。结论:RNA干扰技术可以在原代培养的小鼠脾淋巴细胞中发挥特异性干扰作用，产生抑制IL-1α分泌的效果，为IL-1α的基因治疗开拓了新途径。     

RNA干扰endophilin A2抑制大鼠海马神经元突触囊泡内吞

 目的:探讨内吞蛋白(endophilin)A2对大鼠海马神经元突触囊泡内吞的影响。方法:设计干扰endophilin A2的小分子干扰片段,通过Western blot的方法筛选出针对endophilin A2有效的特异性干扰片段;用免疫荧光的方法验证干扰片段对神经元内源性endophilin A2的干扰效果;利用双全细胞膜片钳的方法,记录不同刺激方案下的兴奋性突触后电流(excitatory postsynaptic currents,EPSCs)的情况,以明确endophilin A2对突触囊泡循环的影响。结果:(1)免疫荧光结果显示endophilin A2的干扰片段能显著减少海马神经元内源性endophilin A2的表达(P<0.05);(2)双全细胞膜片钳结果显示,0.1 Hz的低频刺激下,干扰endophilin A2表达的神经元EPSCs大小与阴性对照组没有明显差异;而无论是单串高频刺激下还是多串高频刺激下,干扰endophilin A2表达的神经元标准化EPSCs的下降程度都明显增强(P<0.05)。结论:(1)成功筛选出特异性干扰endophilin A2的有效干扰片段;(2)干扰endophilin A2的表达不影响海马神经元突触囊泡胞吐;(3)干扰endophilin A2的表达可抑制大鼠海马神经元突触囊泡内吞。     

人CDK2基因RNAi慢病毒载体的构建与鉴定

目的： 构建人细胞周期素依赖蛋白激酶2(CDK2)基因RNA干扰慢病毒载体。〖HJ1.8mm〗方法: 利用Invitrogen公司在线软件设计人CDK2（NM001798）shRNA序列，退火形成ds oligo后克隆到pENTRTM/U6载体的黏性末端，测序，再与慢病毒载体重组，测序鉴定，在脂质体的介导下将慢病毒的包装混合物和CDK2基因重组慢病毒载体转染293FT细胞，包装成病毒后，收集细胞培养上清液，测定病毒滴度。结果: 测序证实pENTRTM/U6- CDK2-shRNA为阳性克隆，与慢病毒载体重组后测序结果显示也为阳性克隆，CDK2基因重组慢病毒载体传染293FT细胞后48 h, 细胞培养上清液，病毒的滴度为6×108TU/L。结论: 成功构建人CDK2基因RNAi慢病毒载体，为研究CDK2在自身免疫病中的应用提供了稳定的转染细胞载体。     

Evaluation of supplemental testing with the Multispot HIV-1/HIV-2 Rapid Test and APTIMA HIV-1 RNA Qualitative Assay to resolve specimens with indeterminate or negative HIV-1 Western blots

BackgroundThe use of Western blot (WB) as a supplemental test after reactive sensitive initial assays can lead to inconclusive or misclassified HIV test results, delaying diagnosis.ObjectiveTo determine the proportion of specimens reactive by immunoassay (IA) but indeterminate or negative by WB that could be resolved by alternative supplemental tests recommended under a new HIV diagnostic testing algorithm.Study designRemnant HIV diagnostic specimens that were reactive on 3rd generation HIV-1/2 IA and either negative or indeterminate by HIV-1 WB from 11 health departments were tested with the Bio-Rad Multispot HIV-1/HIV-2 Rapid Test (Multispot) and the Gen-Probe APTIMA HIV-1 RNA Qualitative Assay (APTIMA).ResultsAccording to the new testing algorithm, 512 (89.8%) specimens were HIV-negative, 55 (9.6%) were HIV-1 positive (including 19 [3.3%] that were acute HIV-1 and 9 [1.6%] that were positive for HIV-1 by Multispot but APTIMA-negative), 2 (0.4%) were HIV-2 positive, and 1 (0.2%) was HIV-positive, type undifferentiated. 47 (21.4%) of the 220 WB-indeterminate and 8 (2.3%) of the 350 WB-negative specimens were HIV-1 positive.ConclusionApplying the new HIV diagnostic algorithm retrospectively to WB-negative and indeterminate specimens, the HIV infection status could be established for nearly all of the specimens. IA-reactive HIV-infected persons with WB-negative results had been previously misclassified as uninfected, and HIV diagnosis was delayed for those with WB-indeterminate specimens. These findings underscore the limitations of the WB to confirm HIV infection after reactive results from contemporary 3rd or 4th generation IAs that can detect HIV antibodies several weeks sooner than the WB.     

BACE1基因RNA干扰质粒的构建及干扰效果的鉴定

目的构建BACE1基因干扰质粒,并研究其在neuro．2a细胞中的表达,为以其为靶点的基因治疗提供稳定转染的质粒。方法选择人、小鼠和大鼠的BACE1基因共有序列为干扰靶点,设计3组连接有GFP的干扰质粒,将构建好的质粒转染nellro-2a细胞,通过RealtimeRT—PCR及Western—blotting的方法分别在RNA及蛋白质水平上检测BACE1的表达,以分析其干扰的效率。结果经酶切及测序证实,插入的DNA片段序列与设计序列完全一致。与空质粒对照组相比,3个干扰靶点对BACE1基因的表达均有不同程度的抑制作用。其中pYr-1．1-siBACE1在mRNA水平及蛋白质水平干扰效果均最好。结论成功构建了BACE1基因的干扰质粒pYr-1．1-siBACE1,并能有效抑制neuro．2a细胞内源性BACE1基因表达,为靶向BACE1基因的治疗提供了有力的工具。     

HIV-1 RNA被有效抑制下T细胞与外周血中HIV-1前病毒DNA

目的:考察HIV-1 RNA被有效抑制下T细胞与外周血中HIV-1前病毒DNA的相关性。方法:对云南地区90例确诊为AIDS,HAART持续治疗时间超过6个月,血浆HIV RNA<50 Copies/ml的患者进行研究,采用Spearmans秩和相关回顾性分析CD4+、CD3+、CD8+、CD4+CD28+、CD4+CD45RA+、CD4+CD45RO+、CD38+、CD8+CD38+T细胞的绝对计数和相对计数与外周血中HIV-1前病毒DNA的相关性,同时考察HIV-1前病毒DNA拷贝数与HAART持续治疗时间的相关性。将90例患者根据HAART后CD4+T细胞绝对计数分为A(CD4+<200 cells/μl)、B(200≤CD4+≤349 cells/μl)、C(CD4+≥350 cells/μl)3组,考察3组间T细胞亚群的差别。结果:HIV-1前病毒DNA的log拷贝数与CD4+CD45RA+T细胞绝对计数呈负相关(r=-0.231,P<0.05),与CD4+CD45RA+T细胞相对计数呈明显负相关(r=-0.270,P<0.01);与CD38+T细胞绝对计数呈正相关(r=0.250,P<0.05);与HAART持续治疗时间无相关性。B、C组的CD3+T细胞绝对计数明显高于A组(P<0.01);C组的CD8+T细胞绝对计数高于B组的(P<0.05);B、C组的CD4+CD28+T细胞绝对计数和相对计数明显高于A组(P<0.01),C组的CD4+CD28+T细胞绝对计数高于B组(P<0.05);B、C组的CD4+CD45RA+T细胞、CD4+CD45RO+T细胞绝对计数明显高于A组(P<0.01),C组的CD4+CD45RA+T细胞、CD4+CD45RO+T细胞绝对计数高于B组(P<0.05),B、C组的CD4+CD45RO+T细胞相对计数高于A组(P<0.05);B、C组的CD8+CD38+T细胞绝对计数低于A组(P<0.05),B组的CD8+CD38+T细胞相对计数低于A组(P<0.05);C组的CD38+T细胞绝对计数高于A组(P<0.05)。A、B、C组的HIV-1前病毒DNA的log拷贝数分别为3.561±0.297 9,3.605±0.277 6,3.434±0.289 1(copies/ml),3组间无显著性差异(P>0.05)。结论:经过HAART治疗后HIV-1前病毒DNA可能处于稳定状态,HIV-1前病毒DNA拷贝数只是某些T细胞亚群数量改变的原因之一。     

RNA干扰Skp2基因抑制T47D乳腺癌细胞生长

目的构建S期激酶相关蛋白2（skp2）RNA干扰真核细胞表达载体,研究skp2基因沉默对乳腺癌T47D细胞生长的抑制作用。方法应用Ambion公司在因特网上的设计程序设计小干扰RNA。构建3个不同的重组体转染T47D细胞,RT-PCR和Western Blotting检测skp2基因表达,细胞计数分析Skp2RNA干扰对肿瘤细胞增殖的影响。结果重组体经PCR和测序证实准确连接。转染重组体的细胞skp2的表达在mRNA和蛋白水平均明显下降。重组体转染的细胞增殖明显降低。结论用RNA干扰下调skp2表达抑制乳腺癌细胞生长,skp2可能是乳腺癌治疗的潜在靶点。     

Reciprocal transactivation between HIV-1 and other human viruses

A variety of rare clinical syndromes are seen with strikingly increased prevalence in HIV-1-infected individuals, many with underlying viral etiologies. The emergence of these diseases in AIDS reflects a reduction in the ability of the immune system to mount an adequate defense against viruses in general due to the damage inflicted to the immune system by HIV-1 infection. However, in many cases, it has been found that HIV-1 can enhance the level of expression and hence the life cycle of other viruses independently of immunosuppression through specific interactions with the viruses. This can occur either directly by HIV-1 proteins such as Tat enhancing the activity of heterologous viral promoters, and/or indirectly by HIV-1 inducing the expression of cytokines and activation of their downstream signaling that eventually promotes the multiplication of the other virus. In a reciprocal manner, the effects of other viruses can enhance the pathogenicity of HIV-1 infection in individuals with AIDS through stimulation of the HIV-1 promoter activity and genome expression. The purpose of this review is to examine the cross-interactions between these viruses and HIV-1.     

Evaluation of the NucliSens EasyQ HIV-1 v1.1 and RealTime HIV-1 kits for quantitation of HIV-1 RNA in plasma

Human immunodeficiency virus type-1 (HIV-1) RNA viral load is an important biomarker to evaluate the therapeutic efficacy of antiretroviral drugs and to monitor disease progression in HIV-infected individuals. We compared HIV-1 RNA quantitation between two different kits, the NucliSens EasyQ^® HIV-1 v1.1 (EasyQ, bioMérieux) and RealTime HIV-1 (RealTime, Abbott), using HIV-1 RNA quality control (QC) materials, cell-cultivated viruses, and the plasma samples of 104 patients with HIV. Correlation between the two kits for HIV RNA-1 quantitation with clinical samples was high (R = 0.91). Based on results obtained with quality control standards, the reproducibility of the RealTime kit was higher than the EasyQ kit: the viral load value and coefficient of variation of each kit was 4.11 ± 0.136 and 3.3% for EasyQ and 3.55 ± 0.042 and 1.2% for RealTime, respectively (P < 0.002).This is the first comparative analysis of the detection limit and reproducibility of two different quantitation kits using clinical plasma samples from Korean HIV-1-infected patients. It will serve a useful reference to determine correction values for each HIV-1 RNA quantitation kits and to choose an appropriate assay kit for each laboratory.     

核糖核酸干扰

The phenomenon of RNA interference (RNAi) is highly conserved mechanism in the organism evolution. As a immune system , RNAi is a ubiquitous mechanism against invading microorganism in plant and animal cells. Recently, it has been found that RNAi is the process by which double-strand RNA (dsRNA) directs sequence - specific degradation of messenger RNA and the mediations of sequence specific messenger RNA degradation are 21 - and 23 - nucleotide small interfering RNAs that generate by ribonuclease from endogenous longer dsRNA or by transfectious technics from heterologous dsRNA. Over the past few years,the way in which cells respond to dsRNA by silencing homologous genes has revealed a new regulating paradigm in biology.