艾滋病痴呆综合征病人HIV-1tat基因多态性及氨基酸序列分析

目的 研究艾滋病痴呆综合征患者体内HIV-1 tat第一外显子基因序列的特征和变异情况,为艾滋病痴呆综合征发病机制的研究提供依据.方法 提取1例艾滋病痴呆综合征病例尸检标本的外周组织(淋巴结、脾脏)和中枢神经组织(脑膜、额叶灰质、额叶白质、颞叶、基底核)共7个部位的基因组DNA,巢式PCR扩增HIV-1 tat第一外显子基因,与克隆载体pGEM-T连接,经转化、氨苄青霉素和蓝白斑筛选出阳性克隆,每个部位挑取5个菌落测序,测序结果利用BioEdit、MEGA4软件比对并生成系统进化树、计算基因距离和同义/非同义替换值(ds/dn),分析氨基酸位点的改变.结果 该病例感染的病毒是HIV-1 B亚型,分离自不同组织的HIV-1 tat第一外显子基因序列存在差异;与标准序列相比,该病例的HIV-1tat第一外显子基因编码的氨基酸序列有16个位点发生了变异,并且中枢各部位部分氨基酸位点的变异与外周不同,特别是中枢基底核5个序列及颞叶1个序列Q54R的变异值得关注.结论 艾滋病痴呆综合征患者体内,HIV-1 tat第一外显子序列与标准序列存在差异,并且在外周和中枢不同部位中存在的变异不同,这些变异是否与艾滋病痴呆综合征的发病机制有关,还有待进一步研究.

Abstract：

Objective To study the variation and characteristics of HIV-1 tat exon 1 gene from a patient with AIDS dementia complex( ADC), so as to research the pathogenesis of ADC. Methods The tat gene was amplified with nested PCR from genomic DNA which was extracted from lymph node, spleen and different brain tissues( meninges, grey matter from frontal cortex, white matter from frontal cortex, temporal cortex and basal ganglia) of a patient who died of ADC. PCR products were cloned into the pGEM-T vector,after transformation and selection by ampicillin and blue/white spotting. Five of positive clones were sequenced. HIV-1 tat sequences were processed with BioEdit and MEGA4. With the softwares, Neighbor-Joining tree, p-Distances, values of ds/dn, and analysis of amino acid motifs were all done. Results The samples were all identified as HIV-1 B and genetic variation exists in HIV-1 tat isolated from different tissue;Compared with HXB2, sixteen sites of the amino acid seque nce coded by the HIV-1 tat gene which was isolated from the patient changed. In addition, part of the changes were different between periphery and brain,especially, the five Q54R changes from basal ganglia and one Q54R change from temporal cortex are deserve to follow with interest. Conclusion Variations exist in the HIV-1 tat genes extracted from the ADC patient and the variations from peripheral and central nerve tissues were different, whether the variations concerned with the pathogenesis of ADC need more research.     

ADC及非ADC患者外周和中枢HIV-1 tat基因多样性分析

目的 研究艾滋病痴呆综合征（ADC）及非ADC患者外周和中枢神经系统（CNS） HIV-1 tat基因的多样性,为HIV进化、入侵CNS的机制以及ADC发病机制研究提供依据。方法 提取一例非ADC患者（有广泛的脑动脉粥样硬化）及一例ADC患者尸检标本的外周脾脏和CNS基底核部位的基因组DNA,巢式PCR扩增HIV-1 tat第一外显子基因,与克隆载体pGEM-T连接,经转化、氨苄西林和蓝白斑筛选出阳性克隆,每个部位挑取5个菌落测序,测序结果利用BioEdit、MEGA4软件比对并生成系统进化树、计算基因距离和同义/非同义替换值（ ds/dn）,研究HIV tat基因在外周和CNS的多样性。结果 ADC和非ADC患者来源的HIV-1 tat基因均存在变异,ADC患者tat基因进化时中枢和外周的区室化效应明显高于非ADC患者,ADC患者外周脾脏和CNS基底核的tat基因之间的差异比非ADC患者更大。dn/ds值显示,两例患者体内HIV-1自身变异起主要作用,而机体倾向于清除有害的非同义突变。结论 ADC和非ADC患者外周和CNS中tat基因变异的区室化效应不同,其原因推测与病毒入侵CNS的途径有关,CNS中HIV基因变异与ADC的关系仍需进一步研究。     

艾滋病痴呆综合征患者HIV-1B gp120基因的克隆及真核表达

目的 克隆艾滋病痴呆综合征(ADC)患者体内不同部位的HIV-1B gp120基因,并在人神经胶质瘤细胞U87中表达.方法 分别以一例ADC患者尸检标本的外周(淋巴结)和中枢(脉络丛、大脑枕叶白质)来源的基因组DNA为模板,PCR扩增HIV-1 gp120基因,序列测定后,将目的基因插入表达载体pcDNA3.1(+),构建重组表达载体gp120/pcDNA3.1(+),将所构建的重组表达载体用脂质体法转染人神经胶质瘤U87细胞,间接免疫荧光法测定HIV-IB gp120的表达情况.结果 克隆了ADC患者体内外周淋巴结、脉络丛、大脑枕叶白质3个部位的HIV-1B gp120基因,所构建的表达质粒gp120/pcDNA3.1(+)转染U87细胞后可表达目的蛋白.结论 ADC患者不同部位来源的HIV-1B gp120基因均可在U87细胞中表达,为进一步研究HIV-1B gp120包膜蛋白的神经毒性及其作用机制提供条件.     

HIV-1C亚型nef基因构建的DNA质粒诱导小鼠免疫反应的研究

目的构建表达中国流行株HIV-1C亚型调控nef基因的重组质粒pVAX-nef，并免疫BALB／c小鼠，观察其免疫效果，为探索新型HIV DNA疫苗提供数据。方法利用分子生物学技术，将nef基因克隆到pVAX，并在体外进行表达与鉴定。以纯化的Nef蛋白作为包被抗原，用ELISA检测其体液免疫反应，用ELISPOT检测其细胞免疫反应。结果重组质粒pVAX-nef成功构建。接种小鼠后2周，ELISPOT结果显示产生了针对HIV特异的CD4和CD8细胞抗原表位的免疫应答，且与免疫剂量存在一定的正相关性。ELISA实验诱导产生了抗HIV-1特异性抗体，其中40μg免疫组诱导的抗体水平最高。结论重组质粒pVAX-nef免疫小鼠后可有效地诱导机体产生细胞免疫和体液免疫反应。     

HIV-1感染的分子生物学机制

ＨＩＶ－１（人类免疫缺陷病毒一型）诱发艾滋病的结论目前已得到广泛认同，有关ＨＩＶ－１病毒及受体细胞的分子结构、ＨＩＶ－１感染的分子生物学机制和病毒复制周期中的基因调控功能的研究已有许多报道，现仅就上述问题作一综述     

基线极高HIV-1 RNA水平对初治HIV-1感染者外周血total HIV-1 DNA的影响

目的:观察基线HIV-1 RNA > 50万copies/mL的HIV-1感染者,在高效抗反转录病毒治疗（highly active antiretroviral therapy,HAART）前后外周血totalHIV-1 DNA的变化。方法:从国家十二五科技重大专项课题中选取基线HIV-1 RNA > 50万copi...     

湖北省HIV-1流行株gag基因序列测定及亚型分析

目的 了解湖北省HIV-1感染者流行毒株亚型分布和流行趋势.方法 随机采集湖北省HIV-1感染者的抗凝全血标本,分离血浆,提取病毒RNA,用套式聚合酶链反应扩增HIV-1病毒gag基因,并进行序列测定和亚型分析.结果 对80份HIV-1感染者的样品进行扩增,得到了62份样品的HIV-1基因片段.共发现7种HIV-1亚型和流行重组株.泰国B'亚型占11.3％ (7/62),欧美B亚型占4.8％ (3/62),G亚型占4.8％ (3/62),CRF07-BC占22.6％ (14/62),CRF08-BC占6.5％(4/62),CRF01-AE占48.4％(30/62),CRF15-01B占1.6％ (1/62).在湖北省发现了CRF15-01B和G亚型.结论 湖北省存在多种HIV-1亚型和流行重组型,CRF01-AE、CRF07-BC两种重组亚型毒株为目前湖北省HIV-1流行优势毒株,应加强对HIV-1毒株亚型变异的监测,及时调整防治策略.     

重组腺病毒HIV-1 vpr基因的构建和表达

目的 构建携带HIV-1 vpr基因的重组腺病毒,使CD4 T淋巴细胞C8166内源性的高表达Vpr蛋白.方法 利用AdEasy-1系统, 通过将含有目的 基因片段的穿梭载体pAdTrack-CMV-vpr和骨架质粒pAdEasy-1在BJ5183细菌内同源重组的方法构建重组腺病毒质粒Ad-vpr, 用脂质体法将重组质粒转染至HEK293A细胞包装, 获得重组腺病毒Ad-vpr, 荧光显微镜观察Ad-vpr感染C8166细胞GFP的表达 , Western blotting鉴定Vpr在C8166细胞内的特异性表达,流式细胞术检测Ad-vpr感染 C8166细胞的效率.结果 成功构建携带HIV-1 vpr基因的重组腺病毒 ,Western blotting结果表明重组腺病毒Ad-vpr感染的C8166细胞内源性的高表达Vpr 蛋白,流式细胞术检测结果表明Ad-vpr感染C8166细胞效率高(44.07±3.62)%.结论 成功构建出携带HIV-1 vpr基因的重组腺病毒,使C8166细胞内源性的高表达Vpr蛋白.     

含HIV-1 gag基因的重组腺病毒5型与35型嵌合病毒免疫效果研究

目的探讨含HIV-1 gag基因的重组腺病毒5型与35型嵌合病毒(rAd5/F35)在BALB/c小鼠中的免疫效果。方法PCR,间接免疫荧光鉴定HIV-1gag基因在重组腺病毒(rAd5/F35-mod.gag)的正确插入和体外细胞水平的表达,用rAd5/F35-mod.gag以不同的方式免疫BALB/c小鼠,ELISA检测小鼠血清中的p24特异性抗体,细胞内细胞因子染色法检测小鼠的特异性细胞毒性T淋巴细胞(CTL)应答。结果重组腺病毒rAd5/F35-mod.gag在体外细胞水平可以很好的表达目的基因gag;在小鼠体内重组腺病毒rAd5/F35-mod.gag可诱导特异性的CTL应答和血清IgG抗体反应,用rAd5/F35单独免疫2次,所诱发的CTL和血清IgG反应最强。但Ad5初次感染后,产生的抗Ad5抗体可以抑制rAd5/F35疫苗的特异性免疫反应。结论重组腺病毒rAd5/F35-mod.gag单独免疫可在小鼠体内诱导特异性的CTL应答和血清IgG抗体反应。只改变Ad5纤突蛋白Fiber,不能避免抗Ad5抗体的抑制作用。     

河北省HIV-1流行株的env基因序列测定和亚型分析

目的了解河北省HIV-1亚型的分布特点和传播方式,推测流行时间,预测流行趋势。方法采集HIV感染者的全血样品,分离外周血单核细胞(PBMC),提取前病毒DNA,使用套式聚合酶链反应(nested-PCR),扩增HIV-1的env基因的C2-V3区并进行序列测定和亚型分析。结果对22份HIV-1感染者的样品,扩增得到了18份HIV-1envC2-V3基因片段,经序列测定和基因分析鉴定出3种HIV-1M亚群基因亚型,即:B′、CRF-BC和C亚型。B′亚型的组内基因离散率为7.84%±3.14%(n=14),基因序列与云南瑞丽株rl42(泰国B亚型)相近;2株CRF-BC亚型与广西毒株的基因离散率为4.60%。与血液途径感染有关的人员均为B′(泰国B)亚型。结论目前,在河北省发现了3种HIV-1亚型。输供血途径中B′亚型仍是主要的流行亚型,可能来源于云南吸毒人群。HIV-1B′亚型在河北省的流行时间大约为7~9年。     

Olfactory deficits in HIV-infected patients with and without AIDS dementia complex

The aim of the present study was to examine the effect of HIV infection on odour memory. Recognition and identification olfactory tests were administered to six groups of patients defined according to a decrease in cellular immunity: asymptomatic HIV seropositive (HIV+), symptomatic HIV+, HIV+ AIDS, and three groups with a mild, moderate, and severe degree of dementia (AIDS dementia complex [ADC]). Consistent with the literature, the general results show that HIV infection is associated with a decrease in olfactory ability. In addition, a polynomial linear trend analysis indicates a constant decrease in performance from the first to the sixth group of patients, related to the number of CD4 T lymphocytes circulating and to the severity of the pathology. An interesting result regards the drop in performance exhibited by ADC patients on the identification task. Reasonably, such an effect is not attributable to a decline in olfactory ability only, bit rather to a severe semantic memory deficit. It follows that the two tasks used here can be useful clinical supports to discriminate between the mental operations involved in a low cognitive demand task (recognition) and in a high cognitive demand task (identification).     

Dendritic cells transfected with the nef genes of HIV-1 primary isolates specifically activate cytotoxic T lymphocytes from seropositive subjects

The HIV-1 Nef protein down-modulates surface expression of MHC class I proteins. Primary infected T lymphocytes thus escape lysis by cytotoxic T lymphocytes (CTL). In contrast, during HIV-1 infection there are strong CTL responses to several HIV proteins, and there is mounting evidence that CTL are critical for controlling the virus. The present study was carried out to assess Nef protein-cell interaction as it occurs in naturally infected antigen-presenting cells. To evaluate the presentation of peptides derived from viral antigen to CTL, we transfected nef genes obtained from peripheral blood mononuclear cells of HIV-1-seropositive subjects into dendritic cells isolated from monocytes of healthy donors. We demonstrate that expression and subsequent processing of Nef by transfected dendritic cells did not alter the presentation of an immunodominant epitope of Nef to CTL of HIV ⁺ subjects. However, mutations in nef gene sequences from primary isolates may abolish this presentation by a mechanism that probably interferes with protein processing.     

Natural antibodies to HIV-tat epitopes and expression of HIV-1 genes in vivo

The tat regulatory protein of HIV-1 was expressed as a fusion protein in E. coli and used as antigen to detect antibodies against HIV-tat (anti-tat) in the serum of HIV-1 infected children and adults. HIV-1-infected children showed a higher frequency (55%) of anti-tat than HIV-1-infected adults (36%). Anti-tat were present in only 15% (3/20) of acutely infected individuals. Forty percent (10/25) of individuals with prolonged HIV-1 infection but without antigen were anti-tat positive. Only 13% (3/23) of HIV-1-antibody-positive individuals with prolonged HIV-1 antigenemia were anti-tat positive and titers of anti-tat antibodies declined with time. Pepscan analysis identified the amino terminus of HIV-tat as the major antibody-binding site. Antibodies to HIV-tat occurred as a harbinger of HIV-1 antigen expression and disappeared thereafter, possibly reflecting the transience of HIV-tat expression. Because of the low antigenicity of HIV-tat, antibodies to this regulatory protein are not a reliable marker for either early HIV-1 infection or subsequent disease progression.     

Immunogenicity of the recombinant adenovirus type 5 vector with type 35 fiber containing HIV-1 gag gene

The immune efficiency of a recombinant adenovirus type 5 with type 35 fiber containing HIV-1 gag gene (rAd5/F35-mod.gag) was investigated in BALB/c mice, in which the rAd5/F35-mod.gag was firstly identified with PCR, then transfected to 293 cells and the in vitro expression level of Gag protein was determined by Western blotting and indirect immuno-fluorescent assay. Mice were immunized with intramuscular injections of rAd5/F35-mod.gag, rAd5-mod.gag or DNA and were boosted after 3 weeks. To test the effect of pre-existing anti-viral immunity on immunization, mice were also injected with Ad5-GFP vector and then immunized 4 and 7 weeks later with Ad5/F35-mod. gag vector. The P24-specific IgG antibody in sera of immunized mice was determined by ELISA and the specific cytotoxic T lymphocyte (CTL) response was assayed by intracellular cytokine staining. It was demonstrated that the rAd5/F35-mod. gag vector could express efficiently the HIV Gag protein in 293 cells in vitro and induce strong HIV-specific immune responses in vivo. The strongest CTL and serum IgG response occurred when mice were immunized twice with injection of rAd5/F35 alone, but the anti-Ad5 antibody after primary infection with adenovirus could inhibit the specific immune responses induced by rAd5/F35 vector. It is concluded that single immunization with recombinant adenovirus rAd5/F35-mod. gag can induce specific CTL and serum IgG antibody responses in mice, but the immunogenicity of rAd5/F35 is comparably weaker than that of rAd5.