含密码子优化型HIV-1 gp120基因重组腺病毒的构建及其免疫效果研究

目的 构建能表达野生型和密码子优化型人免疫缺陷病毒Ⅰ型(HIV-1)B亚型中国流行株gp120基因的非复制型腺病毒。方法 按哺乳动物细胞偏好的密码子对HIV-1B亚型中国流行株Ch gp42的gp120基因进行优化，合成优化基因。将野生型和密码子优化的gp120基因插入穿梭质粒，再与腺病毒骨架质粒pAdEasy-1共转化E．coli BJ5183，获得重组子，转染293细胞后获得重组病毒。分别以两种重组腺病毒疫苗免疫小鼠，ELISA检测小鼠血清中的特异性抗体，乳酸脱氢酶法检测小鼠细胞毒性T淋巴细胞(CTL)反应。结果 获得两株重组腺病毒rAd-wt．gp120和rAd．mod．gp120，能正确表达Gp120。rAd-mod．gp120比rAd-wt．gp120蛋白表达水平明显提高。重组腺病毒免疫小鼠后能产生HIV-1特异性的抗体及CTL反应，rAd-mod．gp120组明显优于rAd-wt．gp120组。结论 成功构建了表达野生型和密码子优化的HIV-1 gp120基因的重组腺病毒，能诱导HIV-1特异性体液和细胞免疫反应。     

HIV-1 C亚型密码子优化gp120负载人DC疫苗的构建及体外功能

目的构建HIV-1C亚型gp120负载人树突状细胞(dentriti ccell,DC)疫苗,并对其体外功能进行初步检测。方法利用Amaxa细胞核转染技术将pcDNA3.1-gp120质粒转染至人成熟DC,以Western blot检测gp120的表达。通过流式细胞仪检测DC表面共刺激分子的变化、混合淋巴细胞反应、CD8+T细胞表面活化分子CD25的表达及其分泌IFN-γ的变化。结果通过Western blot检测,gp120在DC中得到了正确表达。经流式细胞仪检测,DC表面分子CD80表达率由刺激前的33.34%上升至43.20%,CD86表达率由刺激前的60.08%上升至90.34%;负载gp120DC刺激淋巴细胞增殖率为86.72%;CD8+T细胞表面分子CD25表达率由刺激前的5.27%上升至74.21%,IFN-γ的表达率达37%。结论负载了HIV-1gp120的人树突状细胞能够显著刺激淋巴细胞的增殖、增强CD8+T细胞表面活化分子CD25表达以及促进CD8+T细胞分泌IFN-γ,为下一步DC治疗性疫苗的体内研究奠定基础。     

携带中国株HIV-1 gp120基因的重组腺病毒的构建及其感染巨噬细胞的形态学研究

目的: 构建携带中国株HIV-1 gp120基因并可感染小鼠骨髓来源巨噬细胞(BMM)的重组腺病毒。方法: 利用AdMax腺病毒构建系统,以双质粒共转染人胚肾转化细胞293Ad5⁺细胞,完成重组腺病毒载体包装,并进一步扩增和纯化。通过ELISA测定gp120的蛋白产量,以确认目的基因重组与表达成功。以Karber法对病毒进 行TCID₅₀滴度测定,利用BMM进行感染复数(MOI)流式细胞术测定,并利用荧光显微镜观察细胞活化形态。结果: 成功构建AdMax-HIV-1 gp120(简称Ad-gp120)及其对照病毒(Ad-GFP),其滴度分别为10^8.3和10^8.1 TCID₅₀/mL。这些病毒可感染BMM,MOI测定结果表明2种重组腺病毒感染BMM和293Ad5⁺细胞的能力接近,验证了上述TCID₅₀滴度结果。Ad-gp120可在293Ad5⁺细胞中表达gp120蛋白,并可感染和诱导BMM相关形态改变。结论: 成功构建Ad-gp120,其感染可致BMM出现形态发生改变。     

人胸腺基质淋巴生成素基因重组腺病毒载体的构建及表达

目的: 构建含人胸腺基质淋巴生成素基因(TSLP)的重组腺病毒载体并表达, 以研究其免疫学功能。方法: 将由人胚肺细胞扩增得到的TSLP基因, 克隆于真核表达载体pcDNA3. 1中, 再亚克隆至穿梭质粒pShuttle中, 并与腺病毒骨架载体pAdEasy -1共同转化大肠杆菌。以获得的重组质粒线性化后转染HEK293细胞, 并包装成病毒颗粒。采用PCR法对重组腺病毒基因进行鉴定, 并以Westernblot检测TSLP蛋白的表达。结果: 通过细菌内同源重组, 成功构建带有人胸腺基质淋巴生成素基因的重组腺病毒质粒, 转染 293细胞后, 包装的重组病毒经PCR检测表明, 基因组含有目的基因,病毒的滴度可达 1×1011pfu/L。Westernblot证实, 感染的肿瘤细胞中有相应基因产物的表达。结论: 通过菌内重组可高效制备带有特定基因的重组病毒。所制备的Ad -TSLP可成功表达相应基因产物, 为进一步研究这一新型细胞因子的功能奠定了基础。     

含HIV-1 gp120基因的重组腺相关病毒和重组腺病毒疫苗联合免疫的研究

目的 探讨含HIV-1 gp120基因的重组腺相关病毒(rAAV)和重组腺病毒(rAdV)疫苗在BALB／c小鼠中联合免疫的效果。方法 将密码子优化的HIV-1 gp120基因分别插入腺相关病毒(AAV)和腺病毒(AdV)载体质粒，构建含该基因的rAVV和rAdV载体疫苗。将两种疫苗以不同的联合方式免疫BALB／c小鼠，ELISA检测小鼠血清中的gp120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 两种重组病毒均可表达目的基因gp120；在小鼠体内两种重组病毒联合免疫可诱导特异性的CTL应答和血清1gG抗体反应，但用rAAV初免2次，再用rAdV加强3次所诱发的CTL和血清1gG反应最强。结论 rAAV和rAdV疫苗联合免疫可在小鼠体内诱导特异性的CTL应答和血清1gG抗体反应。     

构建重组腺病毒的新策略

重组腺病毒作为基因载体具有很多优越性，因此极大地引发了人们的研究兴趣．构建第一代和第二代腺病毒的方法各式各样，大体上可分为两类：一类是DNA直接在哺乳动物细胞内进行重组，另一类是先在细菌中构建好病毒DNA再转染哺乳动物细胞．而第三代腺病毒因缺失了大部分的病毒基因，构建时需要辅助病毒．几年前，腺病毒的构建还是一项耗时费力的工作，现在已经有了许多优化构建过程的新策略。     

人LIGHT基因的克隆及其重组腺病毒载体的构建

目的 克隆人LIGHT基因，构建其重组腺病毒载体，以研究LIGHT过表达与腺病毒感染对细胞生长的影响。方法 用RT-PCR法从人外周血单个核细胞（PBMC）中克隆人的LIGHT全长基因。将LIGHT cDNA克隆到穿棱载体pAdTrack-CMV-LIGHT重组质粒中，经酶切线性化后，将重组质粒pAdTrack-CMV-LIGHT和骨架质粒pAdEasy-1，以电穿孔法共转染大肠杆菌BJ5183，获得重组腺病毒质粒。最后，将线性化的重组腺病毒质粒转染293细胞包装获得重组腺病毒，用荧光显微镜、PCR及Western blot分析LIGHT基因的表达。结果 用RT－PCR法从人的PBMC中，扩增出723bp的cDNA，测序证实为人LIGHT基因。荧光显微镜、PCR及Western blot证实，LIGHT重组腺病毒可感染293细胞，并在293细胞内进行有效的复制。结论 成功地克隆了人LIGHT基因，并构建了其重组腺病毒载体，为进一步研究LIGHT基因的功能提供了条件。     

密码子优化提高重组腺病毒中人轮状病毒G1VP7和G3VP7基因的表达量

目的 通过密码子优化提高重组腺病毒中人轮状病毒G1VP7和G3VP7基因的表达量.方法 人工合成按照人的优势密码子优化的人轮状病毒G1VP7和G3VP7基因,包装重组腺病毒后,与未优化的相同基因的重组腺病毒用Western Blot方法比较其表达量.结果 密码子优化的人轮状病毒G1VP7和G3VP7基因,与未优化的相同基因的重组腺病毒比较,其蛋白表达量大大提高.结论 密码子优化确实提高了重组腺病毒中人轮状病毒G1VP7和G3VP7基因的表达量,可望满足腺病毒载体疫苗的研发需要.     

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.     

MEK5基因siRNA重组腺病毒表达载体的构建及其对MEK5的表达抑制

目的 构建人MEK5基因的小干扰RNA(siRNA)重组腺病毒表达载体,观察其在胃腺癌SGC7901细胞中对MEK5的表达抑制.方法 设计并合成针对人MEK5基因3个不同部位siRNA靶点的模板DNA序列,以MluⅠ及XhoⅠ克隆入pRNAT-H1.1/Adeno穿梭载体中,将得到的重组穿梭质粒用PmeⅠ线性化后在大肠...     

HIV-1 gp120 AND IMMUNE NETWORK

It has been demonstrated that the immunodominant V3 loop of HIV-1 gp120 and its flanking regions bear sequence and structural homology to the framework and complementarity-determining regions of human immunoglobulins. It has been proposed that the Ig-like domain of gp120 might encode idiotypes and in this way permit HIV-1 entry into the immune regulatory network. This notion is strongly supported by results demonstrating that the anti-V3 loop and anti-Ig antibodies of healthy individuals share complementary structure and that V3 reactive antibodies are present in HIV-negative sera. This might be the mechanism by which HIV induces immunological abnormalities, and it should be taken into consideration in AIDS vaccine development.     

Potency of HIV-1 envelope glycoprotein gp120 antibodies to inhibit the interaction of DC-SIGN with HIV-1 gp120

The interaction of DC-SIGN with gp120 provides an attractive target for intervention of HIV-1 transmission. Here, we have investigated the potency of gp120 antibodies to inhibit the DC-SIGN-gp120 interaction. We demonstrate that although the V3 loop is not essential for DC-SIGN binding, antibodies against the V3 loop partially inhibit DC-SIGN binding, suggesting that these antibodies sterically hinder DC-SIGN binding to gp120. Polyclonal antibodies raised against non-glycosylated gp120 inhibited both low and high avidity DC-SIGN-gp120 interactions in contrast to polyclonal antibodies raised against glycosylated gp120. Thus, glycans present on gp120 may prevent the generation of antibodies that block the DC-SIGN-gp120 interactions. Moreover, the polyclonal antibodies against non-glycosylated gp120 efficiently inhibited HIV-1 capture by both DC-SIGN transfectants and immature dendritic cells. Therefore, non-glycosylated gp120 may be an attractive immunogen to elicit gp120 antibodies that block the binding to DC-SIGN. Furthermore, we demonstrate that DC-SIGN binding to gp120 enhanced CD4 binding, suggesting that DC-SIGN induces conformational changes in gp120, which may provide new targets for neutralizing antibodies.     

Factors limiting the immunogenicity of HIV-1 gp120 envelope glycoproteins

Efficient immune responses to HIV-1 gene products are essential elements to the development and design of an effective vaccine. Ideally, both humoral and cellular responses will be optimally elicited. It is therefore important to elucidate any factors that might limit the immunogenicity of HIV-1 proteins that are likely to be included in an effective vaccine. Since the HIV-1 exterior envelope glycoprotein gp120 is a major target for neutralizing antibodies, it is a virtual certainty that this gene product will be a component of any vaccine that seeks to elicit neutralizing antibody responses from the host humoral immune system. We report here the testing of several HIV-1 gp120 variants derived from a primary isolate that appears deficient in eliciting immune responses at both the level of CD4+ help and consequently in the generation of high-affinity IgG antibody responses in small animals. Factors limiting an effective immune response include (a) envelope glycoprotein strain variation decreasing functional T-cell help, (b) alteration of the glycosylation patterns of gp120 by expression in different cell types, and (c) the native structure of gp120 itself, which may limit the elicitation of effective T-cell help during natural infection or during parenteral immunization in adjuvant. Such limiting factors and others should be considered in the design and testing of gp120-based immunogens in small animals and possibly in primates as well.     

HIV-1 gp41蛋白的表达及其免疫反应性

目的高效表达HIV-1gp41基因片段,满足生产HIV体外检测试剂的需要。方法以含HIV-1gp41基因的质粒X1为模板,采用PCR方法扩增出gp41基因,克隆入E1载体构建重组表达质粒E1—1,转化E．coliBL21DE3感受态细胞,经异丙基-D-D-硫代半乳糖苷（IPTG）诱导后,使用镍螯合琼脂糖亲和层析柱（Ni．NTAAgaros）纯化重组蛋白,通过ELISA法检测重组蛋白的免疫反应性和特异性。结果SDS．PAGE鉴定结果表明,重组E1-1蛋白获得了正确的表达;纯化的重组E1-1蛋白纯度〉95％;ELISA检测结果表明,重组E1-1蛋白具有较优的免疫反应性和特异性。结论成功表达出具有较高免疫反应性的重组E1—1蛋白,可应用于HIV体外检测试剂。     

共表达中国株HIV-1 gp120与hIL-6的重组鸡痘病毒研究

目的 构建共表达中国株HIV-1 gp120与人白细胞介素6(IL-6)的重组鸡痘病毒。方法 分别将HIV-gp120基因和hIL-6基因插入到鸡痘病毒表达载体pUTAL复合启动子ATI-P7．5和P7．5串联启动子下游，构建重组鸡痘病毒表达质粒pUTA-GP-IL6。利用脂质体法将重组质粒和鸡痘病毒282E4株共转染鸡胚成纤维细胞。经BUdR加压筛选3次后，重组病毒分别用PCR、间接免疫荧光试验和Western blot进行鉴定，并进行小鼠免疫研究。结果重组病毒基因组中可扩增出1．4kb大小片段，重组病毒感染细胞表面有绿色荧光物质，表达产物的Western blot分析表明重组病毒可表达gp120和hIL-6蛋白。重组病毒可刺激小鼠产生特异性体液免疫应答。结论成功构建了共表达中国株HIV-1 gp120与hIL-6的重组鸡痘病毒，为研制HIV-1基因工程活载体疫苗提供有益的资料。     

RECOMBINATION PROPERTY OF THE HIV-1 gp120 GENE

Using a chimeric primer consisting of the nucleotide sequence derived from the HIV-1 envelope gene coding for the second conserved region of gp120, and the highly conserved sequence derived from the human immunoglobulin gene coding for the V_HIII domain, it has been identified in sera of AIDS patients HIV-1 field isolates carrying the complete and active Chi recombination hot spot (GCTGGTGG). The recombination between the HIV-1 gene coding for the central portion of gp120 and the bacterial gene coding for the clp protease was also demonstrated in vivo. These results point out serious concern that vectored AIDS vaccine candidates carrying the HIV-1 env gene on viral and bacterial vectors could become the source of potentially new infectious diseases rather than an effective instrument for AIDS prevention.     

Circulating gp120 alters the blood-brain barrier permeability in HIV-1 gp120 transgenic mice

The mechanism underlying invasion of the central nervous system by HIV-1 is unclear. We recently demonstrated blood–brain barrier changes in a model of HIV-1 gp120 transgenic mice. To test whether this alteration was intrinsic to the brain endothelium of transgenic mice or depended on circulating gp120, we used brain endothelial cultures from gp120 transgenic and non-transgenic mice and exposed them to serum from gp120 transgenic or non-transgenic mice. We measured permeability to albumin as a marker of functional endothelial integrity. A significant increase in permeability (up to 47%) was observed in transgenic and non-transgenic cultures exposed to serum samples from transgenic but not to those from non-transgenic mice. This permeability was neutralized after immunoabsorption of sera with anti-gp120 monoclonal antibody. These findings demonstrate that the blood–brain barrier alteration in HIV-1 gp120 transgenic mice is due to circulating gp120.     

gp120mAb对gp120抑制大鼠海马脑片CA1区LTP作用的研究

目的探讨人类免疫缺陷病毒Ⅰ型(HIV-1)的包膜糖蛋白gp120特异抗体gp120mAb对gp120引起大鼠海马脑片CA1区的突触传递及可塑性变化的影响.方法应用离体脑片记录技术,记录大鼠海马CA1区的兴奋性突触后电位(EPSP),研究gp120mAb对gp120抑制高频电刺激Schaffer侧支引起的鼠海马长时程增强效应(LTP)作用的影响.结果gp120对高频电刺激(HFS,100 Hz,1 000 ms×2,串间隔20秒,共2次)Schaffer侧支引起的大鼠海马CA1区LTP产生抑制作用,而对其基础EPSP没有影响.用浓度为200 pmol/L的gp120灌流脑片,可引起LTP的维持发生抑制.这种抑制作用可被gp120特异抗体gp120mAb(50 ng/ml)所拮抗.结论gp120mAb可能是通过拮抗gp120抑制海马CA1区的LTP诱发和维持而参与艾滋病痴呆(HIV-1 associated dementia,HAD)的形成.