细菌内同源重组高效制备含绿色荧光蛋白和抗凋亡基因bcl-XL的重组腺病毒载体

目的:制备含绿色荧光蛋白和抗凋亡基因bcl-X_L的重组腺病毒载体。方法:采用PCR方法从质粒pEGFP-C3-bcl-X_L中扩增出bcl-X_L基因,再亚克隆至腺病毒穿梭质粒中,形成转移质粒pAdTrack-CMV-bcl-X_L;然后与pAdEasy-1共转化BJ5183菌,采用细菌内同源重组法构建重组腺病毒质粒pAdEasy-1-gfp-bcl-X_L,筛选同源重组的阳性克隆;抽提的pAdEasy-1-gfp-bcl-X_L经PacI线性化后,再用LIPOFECTAMINE^TM2000介导转染至人胚肾293细胞内包装扩增出重组腺病毒颗粒;采用PCR方法对重组腺病毒进行鉴定;用氯化铯超高速梯度离心纯化获取高滴度的重组腺病毒rAd-gfp-bcl-X_L。结果:由pAdTrack-CMV-bcl-X_L和pAdEasy-1共转化BJ5183菌16-20h后,可获得35%的阳性重组体细菌克隆。由重组质粒DNA经293细胞包装后产生的重组腺病毒,经PCR检测表明含有目的基因bcl-X_L。氯化铯纯化所得重组腺病毒滴度约为65×10¹²PFU/L。结论:用细菌内同源重组法可以高效、简便、快捷地制备出重组腺病毒质粒载体,重组体病毒质粒经293细胞包装、扩增和氯化铯纯化后可制备出高滴度的重组腺病毒颗粒rAd-gfp-bcl-X_L,为人类相关疾病的基因治疗提供良好的基因转染载体。     

携带红色荧光蛋白报告基因的重组腺病毒载体的构建及其体外试验研究

目的: 采用体外连接技术构建含红色荧光蛋白( RFP )报告基因的重组腺病毒载体, 为基因治疗与基因疫苗研究提供重要工具。方法: 将pTurboRFP-N上的含 RFP 基因片段,经酶切连接定向克隆至转移载体pShuttle上,构成重组质粒pShuttle-TurboRFP-N。用I- Ceu I/PI- Sce I双酶切重组质粒pShuttle-TurboRFP-N和骨架质粒pH5'040 pkGFP-II,回收目的片段,连接,获得重组腺病毒载体AdH5'.040.CMV.RFP-N。将其线性化后,经脂质体介导转染至AD293细胞内包装出重组腺病毒颗粒。通过荧光显微镜观察其在AD293细胞内的包装效率和RFP表达情况。扩增并再次感染AD293细胞检测病毒颗粒感染能力,并测定其生物活性及滴度。将所构建的重组腺病毒载体AdH5'.040.CMV.RFP-N与对照腺病毒载体AdH5.CMV.EGFP 在体外感染人肺癌细胞系A549 和乳腺癌细胞系MDA-MB-231。通过荧光蛋白RFP和EGFP的表达,比较它们对以上肿瘤细胞的感染效率。结果: 经酶切鉴定,证明已正确构建重组腺病毒载体AdH5'.040.CMV.RFP-N;经AD293细胞包装成具有感染性的病毒颗粒,并能在真核细胞中高效表达目的基因;扩增纯化后获得重组腺病毒颗粒数为3.6×10¹⁵vp/L,滴度达1.8×10¹³pfu/L。重组腺病毒载体AdH5'.040.CMV.RFP-N感染人肺癌细胞系A549 和乳腺癌细胞系MDA-MB-231的感染效率,高于对照腺病毒载体AdH5.CMV.EGFP (P＜0.05)。结论: 成功构建了携带 RFP 报告基因的重组腺病毒载体,并能够在AD293细胞中高效地表达,对肿瘤细胞的感染效率高。RFP对GFP是一种很好的代替和补充,为基因治疗与基因疫苗研究提供更多的荧光标签。     

绿色荧光蛋白标记的人血管内皮生长因子165基因重组腺病毒载体的构建与鉴定

目的构建与鉴定携带绿色荧光蛋白标记的人血管内皮生长因子165(hVEGF165)基因的重组腺病毒载体Ad5-hVEGF165-GFP。方法将hVEGF165基因进行扩增,并同源重组入表达质粒pAV-MCMV-HA-P2A-GFP,转化入DH5a感受态细胞,得到的转化子经菌落聚合酶链反应(PCR)鉴定和测序鉴定后,通过Ad Max腺病毒包装系统转染HEK293细胞,进行病毒的包装和扩增。包装后镜下观察HEK293细胞,测定腺病毒滴度,Western blot检测重组腺病毒的表达。结果成功构建了重组腺病毒载体Ad5-hVEGF165-GFP,重组腺病毒转染的HEK293细胞出现了明显的细胞病变效应;获得重组腺病毒的滴度为1.106×10~8 IFU/mL;Western blot检测重组腺病毒表达在23 000左右。结论成功获得重组腺病毒载体Ad5-hVEGF165-GFP,为进一步研究基因治疗脓毒症/感染性休克奠定了实验基础。     

重组小鼠干细胞逆转录病毒载体高效基因转染CD41+、UT7、U937和MDA-MB-435细胞

目的:研究重组小鼠干细胞逆转录病毒载体介导基因转染,探索一条高效基因转染的途径,为重组小鼠干细胞逆转录病毒载体在基因转染中的应用提供理论依据和奠定实验基础。方法:①逆转录病毒载体的构建:EC1-4(repeats1-4ofcadherin-5extracellulardomains)基因克隆产物和mutant(Ser222A)MEK1基因克隆产物,Bg1Ⅱ和EcoRⅠ限制性内切核酸酶切割后,克隆进入逆转录病毒表达载体pMSCV。②CD41⁺细胞的获取和细胞培养:从脐带血分离的CD34⁺细胞通过TPO诱导表达CD41,FACS分离CD41⁺细胞。高糖DMEM培养液培养NIH3T3和MDA-MB-435细胞,U937细胞培养在RPMI-1640培养液,UT7细胞是细胞因子依赖性细胞株,Iscove'smodifiedDulbeco's培养液中加入GM-CSF。③测定病毒滴度:逆转录病毒载体转入包装细胞293,36h后收集病毒上清液,感染NIH3T3细胞,流式细胞仪测定病毒滴度。④Westernblot:基因转染CD41⁺、UT7、U937和MDA-MB-435细胞,Westernblot检测基因产物的表达。结果:293细胞产生高滴度MEK1pMSCV病毒:3.1×10⁷,高滴度EC1-4pMSCV病毒:1.0×10⁸。用稀释8倍的病毒转染基因,重组逆转录病毒MEK1pMSCV转染白血病细胞株UT7和U973,GFP阳性细胞(转染阳性细胞)分别是60.73％、72.56％。重组逆转录病毒MEK1pMSCV转染原代培养细胞CD41⁺,GFP阳性细胞为30.57％。重组逆转录病毒EC1-4pMSCV转染人乳腺癌细胞株MDA-MB-435,GFP阳性细胞为97.54％。TPO作用CD41⁺和UT7细胞以及血清对U973细胞的作用,显示出外源mutationMEK基因的dominantnegative的效应,实验组磷酸化的MEK1减少。EC1-4基因转染的MDA-MB-435细胞表达了EC1-4基因产物。结论:重组小鼠干细胞逆转录病毒载体能高效基因转染CD41⁺、UT7、U937和MDA-MB-435细胞,转染的基因能稳定地表达。     

人KLK1和EGFP双顺反子重组腺病毒构建及其在血管平滑肌细胞中的表达

目的：构建携EGFP为报告基因和人组织激肽释放酶1(hKLK1)基因双顺反子的重组腺病毒（Ad-hKLK1-IRES-EGFP）,并观察在自发性高血压大鼠（SHR）血管平滑肌细胞（VSMCs）中的表达变化。方法:通过双酶切质粒pBluescritII KS-hKLK1，将hKLK1基因定向克隆至带有IRES-EGFP的腺病毒穿梭质粒pDC316中，构建成重组穿梭质粒 ，将其与腺病毒骨架质粒BHGloxE1，3Cre共转染293A细胞，经包装并获得重组腺病毒，用PCR、酶切及测序方法对其进行鉴定，测定病毒滴度；用重组腺病毒感染VSMCs，用荧光显微镜下观察到的绿色荧光来测定感染率，用RT－PCR和Western blotting法测定hKLK1基因在VSMCs中的表达。结果:PCR、酶切和测序表明携EGFP的重组穿梭质粒pDC316-hKLK1-IRES-EGFP构建正确，并与骨架质粒在293A细胞中成功包装出重组腺病毒Ad-hKLK1-IRES-EGFP，其滴度为4.5×10¹¹/L。重组腺病毒感染VSMCs后，在荧光显微镜下观察到明亮绿色荧光蛋白表达，感染率高达90％以上，可检测到hKLK1基因的mRNA及蛋白表达，并与感染时间(1 d-7 d) 有显著依赖关系，峰值感染复数为100 MOI。结论:成功构建并包装了携EGFP和hKLK1基因的双顺反子重组腺病毒载体系统Ad-hKLK1-IRES-EGFP；感染VSMCs可检测到基因hKLK1和EGFP的独立共同高表达，该系统为一直观、安全、高效的基因转移系统。     

人血管形成素-1重组腺病毒高效制备

目的：制备人血管形成素-1重组腺病毒,为基因转染心肌缺血区促血管新生研究作准备。方法：人血管形成素-1重组粘粒与DNA末端蛋白复合物混合后以磷酸钙共沉淀法转染293细胞。获得的重组腺病毒经扩增,并进行酶切鉴定。结果：酶切结果显示,重组粘粒中人血管形成素-1基因插入方向正确,所获重组腺病毒带有此基因。重组腺病毒滴度达5.6×10¹¹ pfu/L。结论：所获人血管形成素-1重组腺病毒为E₁、E₃缺陷型重组子,可用于动物体内基因治疗研究。     

携带miR29c重组腺病毒的制备及其促骨髓瘤细胞凋亡作用

目的制备携带miR29c的重组腺病毒Ad5F11p-miR29c,评价miR29c对骨髓瘤细胞凋亡的影响。方法巢式PCR扩增得到hsa-miR29c,将hsa-miR29c基因克隆到腺病毒穿梭质粒pShuttle-CMV,得到pShuttle-CMV-miR29c。鉴定正确后,PmeI线性化并转化含Ad5F11p骨架质粒的BJ5183感受态细胞,重组获得腺病毒载体。PacI线性化的重组腺病毒质粒转染HEK293细胞,制备重组腺病毒Ad5F11p-miR29c。以对照病毒Ad5F11p-EGFP感染人骨髓瘤细胞系SKO-007、U266和XG7,通过流式细胞术确定最佳感染复数。Ad5F11p-miR29c以最佳感染复数感染骨髓瘤细胞,流式细胞术检测miR29c对细胞凋亡的影响。结果 PCR扩增获得miR29c基因,成功将其连接到腺病毒穿梭质粒pShuttle-CMV,经测序鉴定正确。采用Ad-easy系统,成功构建并制备了CMV启动的重组腺病毒Ad5F11p-miR29c。流式细胞术结果显示,Ad5F11p-EGFP对SKO-007和U266细胞的最佳感染复数为150MOI;而XG7为100MOI。Ad5F11p-miR29c以最佳感染复数感染细胞48h后,细胞凋亡率升高。SKO-007细胞的凋亡率达到26.5%,XG7细胞的凋亡率达到46.9%。结论成功制备重组腺病毒Ad5F11p-miR29c,并证实miR29c能够诱导骨髓瘤细胞凋亡。     

人Wilms瘤基因1重组腺病毒Ad5/F35的制备及感染树突状细胞后的鉴定

目的构建人Wilms瘤基因1(WT1)重组腺病毒载体Ad5/F35并鉴定。方法运用不同病毒滴度的Ad5-EGFP和Ad5/F35-EGFP感染黑素瘤患者外周血树突状细胞(DC),用荧光显微镜检测EGFP的表达,选择对DC感染率高的腺病毒;同源重组构建Ad5/F35-WT1腺病毒载体,用免疫细胞化学和流式细胞术(FCM)检测WT1的表达。结果在相同滴度下,腺病毒载体Ad5/F35的感染优于Ad5;成功构建了Ad5/F35-WT1重组腺病毒,免疫细胞化学染色和FCM证实该病毒能有效介导WT1在DC中的表达。结论 Ad5/F35-WT1重组腺病毒能将WT1基因成功导入DC并有效表达。     

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.     

人重组腺病毒rAd-IL-23R的构建与功能鉴定

目的构建表达白介素23受体的人重组腺病毒(rAd-IL-23R),并探究该病毒对人子宫颈癌(HeLa)细胞系增殖的影响。方法采用AdEasyTM系统,将带有IL-23R的穿梭载体与腺病毒骨架载体进行同源重组,构建pAd-IL-23R,酶切消化鉴定,线性化的病毒质粒在HEK-293A细胞中进行病毒包装和扩增,TCID50法测定病毒滴度。CCK-8法检测rAd-IL-23R对HeLa细胞增殖的影响,流式细胞计量术分析和Western blot检测rAd-IL-23R对HeLa细胞凋亡的影响。结果pAd-IL-23R经PacⅠ酶切消化为约30 kb和3 kb的核酸片段,可诱导HEK-293A细胞产生细胞病变,并成功表达IL-23R蛋白;用不同滴度的rAd-IL-23R(0、1和2 MOI)感染HeLa细胞后,rAd-IL-23R对细胞增殖的抑制具有明显的剂量效应(P<0.05),随着MOI增加,细胞凋亡率显著增加(P<0.05),同时cleaved-caspase 3的蛋白表达水平增高。结论成功构建rAd-IL-23R,该重组腺病毒可抑制HeLa细胞增殖并促进凋亡发生。     

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。     

Maturation of the viral core enhances the fusion of HIV-1 particles with primary human T cells and monocyte-derived macrophages

HIV-1 infection requires fusion of viral and cellular membranes in a reaction catalyzed by the viral envelope proteins gp120 and gp41. We recently reported that efficient HIV-1 particle fusion with target cells is linked to maturation of the viral core by an activity of the gp41 cytoplasmic domain. Here, we show that maturation enhances the fusion of a variety of recombinant viruses bearing primary and laboratory-adapted Env proteins with primary human CD4+ T cells. Overall, HIV-1 fusion was more dependent on maturation for viruses bearing X4-tropic envelope proteins than for R5-tropic viruses. Fusion of HIV-1 with monocyte-derived macrophages was also dependent on particle maturation. We conclude that the ability to couple fusion to particle maturation is a common feature of HIV-1 Env proteins and may play an important role during HIV-1 replication in vivo.     

Adenovirus vaccine vectors expressing hepatitis B surface antigen: importance of regulatory elements in the adenovirus major late intron

Adenovirus types 4 and 7 are currently used as live oral vaccines for prevention of acute respiratory disease caused by these adenovirus serotypes. To investigate the concept of producing live recombinant vaccines using these serotypes, adenovirus types 4 (Ad4) and 7 (Ad7) were constructed that produce HBsAg upon infection of cell cultures. Ad4 recombinants were constructed that express HBsAg from a cassette inserted 135 bp from the right-hand terminus of the viral genome. The cassette contained the Ad4 major late promoter followed by leader 1 of the tripartite leader, the first intervening sequence between leaders 1 and 2, leaders 2 and 3, the HBsAg gene, and tandem polyadenylation signals from the Ad4 E3B and hexon genes. Using this same cassette, a series of Ad4 recombinants expressing HBsAg were constructed with deletions in the intervening sequence between leaders 1 and 2 to evaluate the contribution of the downstream control elements more precisely. Inclusion of regions located between +82 and +148 as well as +148 and +232 resulted in increases in expression levels of HBsAg in A549-infected cells by 22-fold and 44-fold, respectively, over the levels attained by an adenovirus recombinant retaining only sequences from +1 to +82, showing the importance of these elements in the activation of the major late promoter during the course of a natural Ad4 viral infection. Parallel increases were also observed in steady-state levels of cytoplasmic HBsAg-specific mRNA. When similar Ad7 recombinant viruses were constructed, these viruses also expressed 20-fold more HBsAg due to the presence of the intron. All Ad4 and Ad7 recombinants produced HBsAg particles containing gp27 and p24 which were secreted in the medium. When dogs were immunized intratracheally with one of these Ad7 recombinants, they seroconverted to both Ad7 and HBsAg to a high level.     

Intracellular processing, glycosylation, and cell-surface expression of the measles virus fusion protein (F) encoded by a recombinant adenovirus

The membrane fusion protein of measles virus (MVF) is a surface glycoprotein which is essential for initiation of viral infection. The F protein mediates penetration of the host cell through a process of membrane fusion between the viral envelope and the host cell plasma membrane. To study the structure-function relationship of the MVF protein, a recombinant adenovirus, Ad5MVF, was constructed which expressed the F protein in mammalian cells. The MVF gene was inserted into the Ad5 genome by homologous recombination, which resulted in replacement of most of the E1 region. This recombinant virus was stable and replicated efficiently in the 293 cell line which complemented the deleted E1 functions. Human 293 cells infected with Ad5MVF synthesized an authentic MVF protein precursor (F0) which appeared to be cleaved efficiently to the F1 and F2 polypeptides. This recombinant F protein was glycosylated, transported to the cell surface, and found to be capable of inducing syncytia formation and hemolysis of monkey erythrocytes. The hemagglutinin protein (HA), provided by a coinfecting adenovirus, was not able to increase the biological activity of the F protein. Treatment of MV or Ad5MVF-infected cells with tunicamycin, an inhibitor of N-linked glycosylation, abolished processing of the F protein. This observation suggests that glycosylation might play an important role in cleavage-dependent activation of the precursor F0 protein or in its transport to the subcellular region where proteolytic cleavage occurs.     

HIV-1 envelope, integrins and co-receptor use in mucosal transmission of HIV

It is well established that HIV-1 infection typically involves an interaction between the viral envelope protein gp120/41 and the CD4 molecule followed by a second interaction with a chemokine receptor, usually CCR5 or CXCR4. In the early stages of an HIV-1 infection CCR5 using viruses (R5 viruses) predominate. In some viral subtypes there is a propensity to switch to CXCR4 usage (X4 viruses). The receptor switch occurs in ~ 40% of the infected individuals and is associated with faster disease progression. This holds for subtypes B and D, but occurs less frequently in subtypes A and C. There are several hypotheses to explain the preferential transmission of R5 viruses and the mechanisms that lead to switching of co-receptor usage; however, there is no definitive explanation for either. One important consideration regarding transmission is that signaling by R5 gp120 may facilitate transmission of R5 viruses by inducing a permissive environment for HIV replication. In the case of sexual transmission, infection by HIV requires the virus to breach the mucosal barrier to gain access to the immune cell targets that it infects; however, the immediate events that follow HIV exposure at genital mucosal sites are not well understood. Upon transmission, the HIV quasispecies that is replicating in an infected donor contracts through a "genetic bottleneck", and often infection results from a single infectious event. Many details surrounding this initial infection remain unresolved. In mucosal tissues, CD4(+) T cells express high levels of CCR5, and a subset of these CD4(+)/CCR5(high) cells express the integrin α?β?, the gut homing receptor. CD4(+)/CCR5(high)/ α4β7(high) T cells are highly susceptible to infection by HIV-1 and are ideal targets for an efficient productive infection at the point of transmission. In this context we have demonstrated that the HIV-1 envelope protein gp120 binds to α?β? on CD4(+) T cells. On CD4(+)/CCR5(high)/ α4β7(high) T cells, α?β? is closely associated with CD4 and CCR5. Furthermore, α?β? is ~3 times the size of CD4 on the cell surface, that makes it a prominent receptor for an efficient virus capture. gp120-α?β? interactions mediate the activation of the adhesion-associated integrin LFA-1. LFA-1 facilitates the formation of virological synapses and cell-to-cell spread of HIV-1. gp120 binding to α?β? is mediated by a tripeptide located in the V1/V2 domain of gp120. Of note, the V1/V2 domain of gp120 has been linked to variations in transmission fitness among viral isolates raising the intriguing possibility that gp120-α?β? interactions may be linked to transmission fitness. Although many details remain unresolved, we hypothesize that gp120-α?β? interactions play an important role in the very early events following sexual transmission of HIV and may have important implication in the design of vaccine strategies for the prevention of acquisition of HIV infection.     

腺病毒细菌重组系统表达Crg-2蛋白的实验研究

目的利用腺病毒的细菌重组系统表达同时具有免疫趋化及血管抑制活性的趋化性细胞因子Crg-2重组蛋白。方法首先在大肠杆菌BJ5183中将穿梭质粒pShuttle-cmv/crg-2与AdE1区基因缺失的骨架质粒pAdEasy-1进行同源重组,筛选后脂质体法转染入具有AdE1区组成性表达的293包装细胞中进行病毒包装、扩增;Westernblot检测病毒感染293细胞的蛋白表达;趋化实验检测感染细胞上清对激活T淋巴细胞的趋化活性。结果穿梭质粒pShuttle-cmv/crg-2与骨架质粒pAdEasy-1重组后,经酶切及PCR鉴定获得重组腺病毒基因组质粒pAd/crg-2;病毒Ad/crg-2经包装并扩增后,用组织培养感染半数剂量法(TCID50)法测定病毒滴度达4×109TCID50/L,感染细胞经Westernblot检测有一接近Mr10000蛋白条带,分泌上清对激活的脾淋巴细胞有明显的趋化作用。结论采用细菌重组法成功获得重组腺病毒Ad/crg-2,可高效表达趋化性细胞因子Crg-2。     

Recombinant adenovirus co-expressing capsid proteins of two serotypes of foot-and-mouth disease virus (FMDV): in vitro characterization and induction of neutralizing antibodies against FMDV in swine

Human adenovirus type 5 (Ad5) has been evaluated as a novel gene delivery vector for the development of live-viral vaccines for foot-and-mouth disease (FMD). In this study, we constructed an Ad5 vector co-expressing the capsid precursor proteins, P1, of FMD virus (FMDV) field strains A24 Cruzeiro and O1 Campos and examined the neutralizing antibody responses in swine after inoculation with the vector. To construct the Ad5 vector, a bicistronic expression cassette containing a cytomegalovirus promoter, the P1 coding sequence of FMDV A24, the internal ribosomal entry site (IRES) of FMDV A12, the P1 coding sequence of FMDV O1 Campos and the coding region of A12 3C protease was inserted into the E1 region of an E1/E3-deleted Ad5. The recombinant adenovirus, Ad5A24+O1, was generated by transfection of 293 cells with full-length pAd5A24+O1 recombinant plasmid DNA. The recombinant Ad5 co-expressed P1 of both A24 and O1 in infected 293 cells and P1 of both serotypes was processed to produce VP0, VP3, and VP1. We further demonstrated the formation of capsid protein complexes by co-precipitation of VP0, VP3, and VP1 with monoclonal antibodies against viral capsid proteins. Swine inoculated with Ad5A24+O1 generated neutralizing antibodies against both A24 and O1. However, the overall neutralizing antibody response was considerably lower than that induced by a commercial FMD vaccine or a monovalent Ad5-A24 vaccine.     

Analysis of the functional relationship between V3 loop and gp120 context with regard to human immunodeficiency virus coreceptor usage using naturally selected sequences and different viral backbones

The human immunodeficiency virus type 1 (HIV-1) gp120 V3 loop plays a predominant role in chemokine receptor usage; however, other linear and nonlinear gp120 domains are involved in this step of the HIV-1 replication cycle. At present, the functional relationship between V3 and these domains with regard to coreceptor usage is unclear. To gain insights into the nature of this relationship in naturally selected viral variants, we developed a recombinant strategy based on two different gp120 backbones derived from CXCR4 (X4)- and CCR5 (R5)-tropic viral strains, respectively. Using this recombinant model system, we evaluated the phenotype patterns conferred to chimeric viruses by exogenous V3 loops from reference molecular clones and samples from infected subjects. In 13 of 17 recombinants (76%), a comparable phenotype was observed independently of the gp120 backbone, whereas in a minority of the recombinant viruses (4/17, 24%) viral infectivity depended on the gp120 context. No case of differential tropism using identical V3 sequence in the two gp120 contexts was observed. Site-directed mutagenesis experiments were performed to evaluate the phenotypic impact of specific V3 motifs. The data indicate that while the interaction of HIV-1 with chemokine receptors is driven by V3 loop and influenced by its evolutionary potential, the gp120 context plays a role in influencing the replication competence of the variants, suggesting that compensatory mutations occurring at sites other than V3 are necessary in some cases.     

Ad5F35-LMP2重组腺病毒免疫效果的研究

目的了解含有EB病毒潜伏膜蛋白2的非复制型重组腺病毒(Ad5F35-LMP2),免疫恒河猴的特异性细胞和体液免疫的效果。方法分别使用高剂量(1.5×1010TCID50/只)、中剂量(1.5×109TCID50/只)、低剂量(1.5×108TCID50/只)Ad5F35-LMP2重组腺病毒,同时设对照组(PBS4.0ml/只)。肌内注射免疫恒河猴,每个月一次,共免疫3次,第0、4、8、12周时使用Elispot方法检测猴外周血EBV-LMP2细胞毒性T细胞应答,同时应用免疫酶方法检测血清中LMP2抗体。结果3个剂量Ad5F35-LMP2腺病毒免疫恒河猴均可以诱导出有效的细胞免疫应答及一定的抗体应答,免疫应答水平的高低与病毒剂量的高低有一定的关系,较高剂量产生的细胞及体液免疫应答水平比低剂量的高。结论Ad5F35-LMP2非复制型重组腺病毒疫苗可以有效的诱导恒河猴产生EBV-LMP2特异性细胞和体液免疫反应。