HIV-1病毒感染因子基因克隆、表达、纯化及其抗体制备的研究

目的制备HIV-1病毒感染因子(Vif)及其抗体。方法用PCR技术从HIV-1NL4·3cDNA质粒中扩增病毒感染因子(vif)基因,vif基因全长为579nt(核苷酸),翻译成含192个氨基酸的蛋白质。将测序鉴定过的vif基因克隆到原核表达载体pET-32a上,以包涵体的形式在大肠埃希菌BL21(DE3)中高效表达,Vif蛋白C端融合6×His标签便于纯化及鉴定。应用酶切鉴定、SDS-PAGE及WesternBlot等方法确保基因片段的正确性及表达蛋白的特异性。间接ELISA法测定兔多克隆抗体滴度。结果成功地获得了高纯度的Vif融合蛋白,纯度可达80%以上。用其制备多克隆抗体滴度可达1∶204800。结论获得高纯度的Vif融合蛋白及其高效价的抗体。     

HIV-1病毒Nef基因克隆、表达、纯化及其抗体的制备

目的:运用基因工程方法制备HIV-1 Nef重组蛋白及其抗体.方法:用PCR技术从HIV-1 H×B2质粒中扩增HIV-1 Nef基因,将测序鉴定过的HIT-1 Nef基因克隆到原核表达载体pET28a( )上,应用酶切鉴定、测序、SDS-PAGE及Western blot等方法鉴定基因片段的正确性及表达蛋白的特异性.纯化的重组蛋白免疫兔3次后,ELISA法测定兔多克隆抗体滴度.用其制备的多克隆抗体通过免疫组织化学方法测定表达Nef基因的内皮细胞.结果:成功地构建了Nef基因的原核表达质粒,测序证明HIV-1 Nef基因全长为621 bp,编码206个氨基酸.在大肠杆菌BL21(DE3)中高效表达的重组蛋白为包涵体的形式.HIV-1 Nef蛋白N端融合6×His标签便于纯化及鉴定.获得的高纯度HIT-1 Nef融合蛋白,免疫动物后,可产生特异的高滴度抗体(ELISA滴度达1∶10000).将转染Nef基因的内皮细胞,应用免疫组化的方法证明其抗体有高度的特异性.结论:构建了高表达HIT-1 Nef蛋白的原核表达系统,制备的Nef重组蛋白免疫动物,获得了特异、高效价的抗体,为研究Nef基因的生物学活性提供了实验材料和依据.     

高效表达重组HIV-1 gp41及在尿液检测中的应用

目的 应用优化的HIV-1 gp41基因,通过原核表达得到高纯度的重组HIV-1 gp41抗原,制备基于重组gp41抗原的尿液HIV-1抗体检测试剂盒,并评价此试剂盒在尿液抗体检测中的灵敏度和特异性.方法 将编码HIV-1B亚型gp41主要抗原表位的基因插入到原核表达载体pET22b中,构建表达质粒pET22b-mgp41.将表达质粒转化B121(DE3)后经IPTG诱导其表达重组抗原rgp41.重组抗原经镍离子亲和层析和分子筛层析得到纯化.将纯化后重组抗原包被ELISA板,对4796份正常人群尿液、641份HIV-1抗体阳件感染者尿液进行HIV-1抗体检测.结果重组抗原经纯化后纯度95%.用本实验中制备的HIV-1抗体尿液检测试剂盒的检测结果显示,此试剂盒灵敏度为100%,特异性为98.52%.结论 本研究中制备的HIV-1尿液诊断试剂盒可以满足HIV感染者初筛实验的需要.     

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基因重组腺病毒载体的构建及表达

目的 构建含有HIV-1 C亚型gp120基因重组腺病毒载体,并在293细胞中表达gp120蛋白.方法 PCR扩增,获得HIV-1 C亚型gp120片段,定向克隆入腺病毒转移载体pTrack-CMV,线性化后转化至含有腺病毒骨架载体pAd-easy-1的大肠埃希菌BJ5183,获得重组子prAd-gp120,PacⅠ酶切纯化后转染293细胞,包装成复制缺陷型重组腺病毒vAd-gp120.结果 经PCR、酶切及DNA测序,插入片段大小、方向正确,获得了具有感染力的vAd-gp120重组腺病毒;通过Western 印迹检测,重组腺病毒在293细胞中表达出分子量为120 kD的蛋白.结论 成功构建了含有HIV-1 C亚型gp120基因重组腺病毒载体,并获得该基因的表达.     

表达HIV-1 B亚型env基因的质粒DNA及腺病毒载体疫苗的免疫原性研究

目的 构建表达中国B亚型HIV-1流行株env基因的DNA及重组腺病毒载体疫苗,将其用于预防或治疗HIV感染.方法 构建质粒DNA疫苗pVR-gp160及重组腺病毒载体疫苗rAdV-gp160.将这两种疫苗以不同的方式免疫BALB/c小鼠,分别采用ELISPOT方法 和ELISA方法 检测免疫小鼠中HIV-1 Gp120特异性细胞免疫反应及抗体反应.结果 DNA疫苗单独免疫及DNA疫苗初免/腺病毒疫苗加强免疫的联合免疫方案皆可诱导较高水平的Gp120特异性细胞免疫反应;而在体液免疫方面,各实验组产生的Gp120特异性抗体水平都较低.结论 所构建的DNA疫苗及rAdV疫苗能有效表达Gp160蛋白,并可有效激活机体的细胞免疫反应.     

表达HIV-1 gag-pol△和gp 140 TM蛋白复制缺陷型重组腺病毒的构建及免疫效果研究

目的构建表达人免疫缺陷病毒Ⅰ型gag-pol△和gp140TM基因的非复制型重组腺病毒.方法首先将HIV-1的gag-pol△和gp140TM基因插入穿梭载体,再与腺病毒骨架质粒pAdEasy-1共转化E.coli BJ5183,获得重组子.转化293细胞后获得重组病毒.重组腺病毒与DNA疫苗联合免疫小鼠,ELISA检测小鼠血清中的抗体.结果获得两株重组腺病毒vAd-gag-pol△和vAd-gp140TM,能正确表达Gp140TM、Gag蛋白以及经剪切加工的P24蛋白,与DNA疫苗联合免疫小鼠后能产生高滴度的HIV-1特异性的抗体.结论成功构建了表达HIV-1结构基因的重组腺病毒,能有效诱导HIV-1特异性抗体.     

表达HIV-1 gag-polΔ和gp140TM蛋白复制缺陷型重组腺病毒的构建及免疫效果研究

目的 构建表达人免疫缺陷病毒Ⅰ型gag-polΔ和gp140TM基因的非复制型重组腺病毒。方法 首先将HIV-1的gag-polΔ和gp140TM基因插入穿梭载体，再与腺病毒骨架质粒pAd Easy-1共转化E．coli BJ5183，获得重组子。转化293细胞后获得重组病毒。重组腺病毒与DNA疫苗联合免疫小鼠，ELISA检测小鼠血清中的抗体。结果 获得两株重组腺病毒vAd-gag-polΔ和vAd-gp140TM，能正确表达Gp140TM、Gag蛋白以及经剪切加工的P24蛋白，与DNA疫苗联合免疫小鼠后能产生高滴度的HIV-1特异性的抗体。结论 成功构建了表达HIV-1结构基因的重组腺病毒，能有效诱导HIV-1特异性抗体。     

Ⅰ型人类免疫缺陷病毒包膜糖蛋白CD4结合位点修饰诱导小鼠体液免疫反应的实验研究

目的 探讨Ⅰ型人类免疫缺陷病毒(HIV-1)包膜糖蛋白(Env) gp120的CD4结合位点(CD4BS)核心区第423、425和431位氨基酸三联突变ING/MKE对其诱导体液免疫反应的影响.方法 构建HIV-1原代毒株06044包膜gp120 ING/MKE三联突变表达载体pcT22-06044 gp120T-ING/MKE(gp120T-ING/MKE),在体外转染的HEK293T细胞表达三聚化野生型gp120Twt蛋白和突变体gp120T-ING/MKE蛋白.免疫BALB/c小鼠后检测结合抗体、中和抗体和骨髓抗原特异性浆细胞.结果 获得真核表达载体gp120T-ING/MKE.转染后,在293T细胞培养上清中检测到了三聚化重组蛋白.末次免疫后14 d,gp120Twt和gp120T-ING/MKE免疫血清中结合抗体滴度都大于1∶1 000,但两组血清抗体滴度无显著差异.突变体组骨髓特异性浆细胞分泌水平和非特异浆细胞水平均低于野生型gp120免疫组.野生型和突变体免疫诱导血清抗体的中和活性均不强.结论 HIV-1包膜蛋白CD4结合区423、425和431位三联突变没有改善gp120蛋白的免疫原性.     

HIV-1 p15(Gag)基因的克隆、蛋白表达及抗体制备

目的 为了研究HIV-1 p15(Gag)的生物学活性,制备HIV-1 p15(Gag)蛋白及其特异性抗体.方法 用PCR的方法扩增编码p15(Gag)基因序列,将其克隆到原核表达载体pET28a( )中表达HIV-1 p15蛋白,分别用His抗体和HIV阳性血清做western blot鉴定目的 蛋白.以纯化目的 蛋白为抗原免疫日本大耳白兔,制备多克隆抗体.通过酶联免疫吸附实验(ELISA),免疫细胞化学法检测抗体滴度及其特异性.结果 原核表达载体pET28 a( )-p15(Gag)成功构建,可在大肠杆菌BL21 (DE3)中诱导表达,得到相对分子质量约20000的p15(Gag)蛋白经western blot鉴定正确.纯化蛋白免疫家兔,制备的多克隆抗体具有较强免疫特异性.结论 得到纯化的HIV-1 p15蛋白,制备的多克隆抗体能够检测自然状态下病毒蛋白p15(Gag),为进一步研究HIV-1奠定了实验基础.     

The transmembrane domain of vesicular stomatitis virus glycoprotein suffices to anchor HIV-1 envelope gp120 expressed by a recombinant vaccinia virus

The shedding of HIV-1 glycoprotein gp120 results from the proteolytic cleavage of its precursor gp160 into gp120 and an anchoring gp41, to which gp120 is non-covalently attached. This report is directed toward the anchorage of gp120 expressed by three recombinant vaccinia virus (rvv): vPE16 expresses wild-type gp160; vvE13 the gp120-vesicular stomatitis virus G transmembrane and cytoplasmic tail (VSVGTMCT) fusion protein; and vvE14 the gp120 with 52 amino acids (aa) from the vector. In order to convert gp120 into an integral membrane protein, a gp120- VSVGTMCT chimerical gene fragment has been constructed and expressed in mammalian cells. This gp120 fusion protein expressed by an rvv, vvE13, has been shown to elicit better immunogenicity and protection against a gp160-expressing tumor cell line than the full-length envelope (env) glycoprotein gp160 in mice. The results show that gp120-VSVGTMCT expressed by vvE13 is not shed because it is membrane associated. The hydrophobic fragment of vesicular stomatitis virus G (VSVG) furnishes an anchor of the chimeric protein just as it does in the native VSVG.     

Role of maternal humoral immunity in vertical transmission of HIV-1 subtype E in Thailand.

The significance of the maternal humoral immune response in relation to vertical transmission of HIV-1 was investigated in 123 mothers infected with subtype E from Thailand. Antibody binding titers to HIV-1 env domains (monomeric gp120, the CD4/gp120 binding site [BS], V3 loop, and gp41) and antibody-mediated neutralization of primary and T-cell line-adapted (TCLA) subtypes B and E HIV-1 isolates were investigated. No correlation between maternal anti HIV-1 antibodies at delivery and vertical transmission of HIV-1 subtype E was found. However, a trend to higher titer antibody-mediated cross-neutralization of a heterologous subtype B TCLA isolate, HIV-1MN, was observed in nontransmitting mothers postpartum. The HIV-1-specific antibody titers in these infected mothers increased significantly from delivery to 6 months postpartum (p < .05), but this was only partially attributable to hemodilution and an additional factor or factors appear to affect humoral immunity to HIV-1 during late pregnancy.     

HIV-1蛋白酶基因的克隆、蛋白表达及抗体制备

目的为了研究HIV-1蛋白酶的生物学活性,制备HIV-1 PR蛋白及其特异性抗体。方法用PCR方法扩增编码PR的基因序列,将其克隆到原核表达载体pET28a(+)中,并表达HIV-1 PR蛋白,用His抗体为一抗做Western blot鉴定目的蛋白。以纯化的目的蛋白为抗原免疫日本大耳白兔,制备多克隆抗体。通过酶联免疫吸附实验(ELISA),免疫细胞化学法检测抗体滴度及其特异性。结果原核表达载体pET28 a(+)-PR成功构建,并可在大肠杆菌BL21(DE3)中诱导表达,得到的PR蛋白经SDS-PAGE和Western blot鉴定正确。用纯化蛋白免疫家兔,制备的多克隆抗体具有较强免疫特异性。结论得到纯化的HIV-1PR蛋白,制备的多克隆抗体能够检测自然状态下病毒蛋白PR,为进一步研究HIV-1奠定了实验基础。     

人源抗人免疫缺陷病毒1型噬菌体抗体库的构建及筛选

目的构建人免疫缺陷病毒１型（ＨＩＶ－１）特异性噬菌体抗体库，制备人源抗ＨＩＶ－１ｇｐ１２０单克隆抗体。方法以半巢式聚合酶链反应（ＰＣＲ）从ＨＩＶ－１感染者外周血单个核淋巴细胞中扩增抗体重链Ｆｄ和轻链（ｋ）基因，与噬菌体载体ｐＣｏｍｂ３连接，构建噬菌体抗体Ｆａｂ组合文库。对抗体库进行３轮吸附－洗脱－扩增的亲和选择后，以ＥＬＩＳＡ法筛选抗ＨＩＶ－１ｇｐ１２０噬菌体抗体，并进行ＤＮＡ序列分析和Ｆａｂ的可溶性表达。结果半巢式ＰＣＲ有效地扩增出Ｆｄ和ｋ基因，以此构建成容量为１９５×１０７的噬菌体抗体库。３轮亲和选择使特异性抗体得到高度富集，抗ＨＩＶ－１ｇｐ１２０噬菌体抗体阳性克隆占３２％。对一阳性克隆抗体基因ＣＨ１和ＣＬ部分ＤＮＡ序列进行了测定，并在大肠杆菌表达出可溶性Ｆａｂ。结论抗ＨＩＶ－１特异性噬菌体抗体库的构建和人源抗ＨＩＶ－１ｇｐ１２０单克隆抗体的制备为今后筛选抗ＨＩＶ中和抗体奠定了基础，具有重要的应用价值。     

德国小蠊细胞色素P450 CYP4G19基因的原核表达及多克隆抗体制备

目的构建细胞色素P450 CYP4G19基因部分片段的原核表达载体并诱导其表达,纯化表达的融合蛋白并制备CYP4G19多克隆抗体。方法应用RT-PCR扩增CYP4G19基因部分片段,产物经T-A克隆、测序鉴定,亚克隆入原核表达载体pET-28a,在大肠杆菌BL21（DE3）中诱导表达,镍离子亲和层析法纯化重组蛋白后,免疫小鼠,获得多克隆抗体,ELISA及Western-blot检测多抗的效价及特异性。结果从德国小蠊cDNA中克隆出一段771bp的亲水性基因片段,在大肠杆菌中诱导表达出约32000Mr、以包涵体形式存在的P450重组蛋白。将纯化、复性的重组蛋白免疫小鼠。得到了滴度高于1：10^6的高效价多克隆抗体。Western-blot显示此多抗能与32000Mr的重组蛋白特异结合,并能识别天然的德国小蠊微粒体P450蛋白。结论利用原核表达的CYP4G19融合蛋白具有良好的免疫原性。制备出效价高、特异性强的抗德国小蠊CYP4G19多克隆抗体,为下一步关于德国小蠊CYP4G19蛋白表达特性及其抗药性功能的深入研究提供了重要的实验工具。     

The envelope glycoprotein of HIV-1 gp120 and human complement protein C1q bind to the same peptides derived from three different regions of gp41, the transmembrane glycoprotein of HIV-1, and share antigenic homology

Gp41, the transmembrane glycoprotein of HIV-1, has been shown to be non-covalently associated with gp120. We have shown that it also binds human C1q. To analyze the interaction site(s) of gp41 with these two molecules, we established an enzyme-linked immunosorbent assay (ELISA) system using recombinant soluble gp41 [amino acids (aa) 539–684] and peptides thereof. In the cell-external part of gp41 three sites (aa 526–538, aa 590–613 and aa 625–655) were found to bind both gp120 and C1q. That gp120 and C1q use the same sites was evidenced by the fact that these proteins competed with each other for the same sites in recombinant soluble gp41 and gp41 peptides. It could be demonstrated by ELISA, that rabbit antibodies against human C1q recognized gp120, and rabbit antibodies against gp120 cross-reacted with C1q. Rabbit anti-gp120, HIV-1-positive human sera and anti-gp120 obtained from such sera agglutinated sensitized sheep erythrocytes with human C1q (EAC1q). These data suggest that in addition to functional homology between C1q and gp120 structural homology between these two molecules exists. This molecular mimicry might become the basis for immunologically relevant autoimmune phenomena.     

Immunogenicity of recombinant Modified Vaccinia Ankara Viruses (rMVA) expressing HIV-1 Indian subtype C gag-protease and env-gp120 genes in mice

India has currently an estimated 5.1 million HIV-infected individuals, and almost 95%of them are infected with subtype C strain. Therefore, it is imperative that a vaccine from locally circulating Indian HIV-1 subtype C be developed which would induce a robust immune response in the recipients. In this study, recombinant Modified Vaccinia Ankara Viruses (rMVA) expressing Indian HIV-1 subtype C envelope and core proteins were tested for their immunogenicity in the Balb/C murine model. Mice were immunized with two doses (10(7) pfu/dose) of recombinant MVA constructs intradermally. Both the constructs produced high levels of antibodies against gag and envelope gp120 and also elicited broad based as well as robust cell mediated immune response as evaluated by IFN-gamma ELISpot assay. These epitopes were distributed through out the length of gag and envelope gp120 proteins.     

Inhibition of myelin formation by HIV-1 gp120 in rat cerebral cortex culture

Summary To study the role of HIV-1 gp120 in loss of myelin in HIV encephalopathy, the binding of gp120 to various types of neural cells and its effects on myelination were examined in rat primary brain culture. Doublestaining of cultured cells with gp120 and specific antibodies for different neural cell types showed that gp120 bound to most of the galactocerebroside (GalC)-positive oligodendrocytes, a small population of type-2-like astrocytes and a few small neurons. Gp120 did not bind to type-1-like astrocytes, most neurons, or to macrophage/microglia. To assay myelination, cells were bathed in a myelination medium containing chick embryo extract and high glucose, with or without gp120. Seven days after the application, myelination in the culture was observed morphologically and by staining with anti-myelin basic protein (MBP) antibody, and was found to be significantly inhibited by the addition of gp120 (50–100 nM). The processes of oligodendrocytes were reduced in length and arborization relative to the control, but MBP production by oligodendrocytes was unaffected. These results show that gp120 can cause a functional disorder of oligodendrocytes and thus could underlie the diffuse loss of mylein sheaths of HIV encephalopathy.