表达狂犬病毒糖蛋白的重组痘苗病毒对狗的免疫效果观察

用表达狂犬病毒糖蛋白的两株重组痘苗病毒对狗口服、划痕和肌肉注射三种途径的免疫效果进行观察。结果口服免疫未见抗体阳转,而划痕和肌注免疫在第七天就能诱导中和抗体。中和抗体滴度达642。以肌肉注射、皮下注射和脚掌注射免疫小鼠,亦获得较好的免疫效果。     

河南省九株狂犬病毒的糖蛋白基因序列分析

目的 了解河南省狂犬病毒与人用、兽用狂犬病疫苗株在糖蛋白基因核苷酸和氨基酸序列水平上的差异,为有效控制狂犬病疫情提供初步的科学依据.方法 以反转录-半套式聚合酶链反应(RT-heminested-PCR)扩增2006年12月分离自河南省信阳市的9株狂犬病毒街毒株,经纯化、克隆、测序后获得9条糖蛋白基因全长序列,采用生物信息学软件构建基因系统发育树,对糖蛋白基因序列和氨基酸序列进行分析.结果 9株狂犬病毒糖蛋白在核苷酸及氨基酸序列水平上彼此的同源性分别为97.6%～98.9%和99.2%～99.8%;9株病毒与CTN疫苗的同源性最高,其核苷酸及氨基酸同源性分别为85.6%～93.0%和91.9%～92.9%;9株病毒与其他疫苗株相比,其核苷酸及氨基酸同源性分别为80.4%～83.3%和87.7%～92.5%;与已知的基因1型狂犬病毒比较,9株病毒糖蛋白氨基酸序列发生了若干位点的氨基酸取代.结论 9株河南省狂犬病毒街毒株均属基因1型,CTN疫苗株可能为目前我国河南省所流行的狂犬病提供较好的保护效果.     

融合基因DNA疫苗pcDNA3/MDC-VP1对柯萨奇病毒B组3型的免疫效果

目的:观察巨噬细胞源趋化因子(MDC)基因与柯萨奇病毒B组3型(CVB3)VP1基因融合基因DNA疫苗pcDNA3/MDC-VP1的免疫效果,为CVB3疫苗的研制提供理论和实验依据。方法:6~8周雄性BALB/c纯系小鼠156只随机均分为6组,分别肌内注射0·9%氯化钠溶液(A组)、pcDNA3(B组)、pcDNA3/MDC(C组)、pcDNA3/VP1(D组)、pcDNA3/MDC加pcDNA3/VP1(E组)、pcDNA3/MDC-VP1(F组),3周注射1次,共3次。每次接种后20d断尾取血,测血清中和抗体效价。第3次免疫后3周,每组20只小鼠腹腔注射含10倍半数致死量LD50的CVB3的病毒液各0·2ml,观察各组小鼠的存活情况;每组剩余的6只小鼠腹腔注射含3倍LD50的病毒液各0.2ml,第7天取血后处死,用于检测血中病毒滴度,称量心脏质量计算心脏体重比。结果:A、B、C、D、E和F组的生存率分别为15%、10%、20%、25%、35%和50%,用Kaplan-Meier进行生存分析表明,F组(pcDNA3/MDC-VP1组)的生存状况好于其他各组;F组的血清中和抗体滴度明显提高、血中病毒滴度显著降低,心肌充血肿胀程度较轻。结论:融合基因DNA疫苗pcDNA3/MDC-VP1能诱导小鼠对CVB3VP1产生更强的免疫应答,提高小鼠生存率。     

恶性疟原虫保护性抗原复合基因—痘苗病毒重组活疫苗株免疫动物后诱发的Th1细胞免疫反应

目的：测定恶性疟原虫－豆苗病毒重组活疫苗侯选株免疫动物后产生白细胞介素－2（IL－2）和干扰素（IFN）的生活学性水平。方法：用MTT法测定了其诱导的保护性细胞免疫反应（Th1细胞免疫反应）。结果：用重组痘苗病毒在免疫家兔及大白鼠4－6kw后血清中IL－2的生物学活性增强,免疫后6wk家兔,大白鼠及小白鼠3种动物血清中IFN的生物学活性水平比免疫前明显升高。结论：恶性疟原虫－痘苗病毒重组活疫苗候选株免疫动物后可诱发机体产生Th1细胞免疫反应。     

恶性疟原虫保护性抗原复合基因-痘苗病毒重组活疫苗株免疫动物后诱发的Th1细胞免疫反应

目的　测定恶性疟原虫 -痘苗病毒重组活疫苗候选株免疫动物后产生白细胞介素 - 2 (IL- 2 )和干扰素 (IFN)的生物学活性水平。　方法　用 MTT法测定了其诱导的保护性细胞免疫反应 (Th1细胞免疫反应 )。　结果　用重组痘苗病毒在免疫家兔及大白鼠 4～ 6 wk后血清中 IL- 2的生物学活性增强 ,免疫后 6 wk家兔、大白鼠及小白鼠 3种动物血清中 IFN的生物学活性水平比免疫前明显升高。　结论　恶性疟原虫 -痘苗病毒重组活疫苗候选株免疫动物后可诱发机体产生 Th1细胞免疫反应     

恶性疟原虫保护性抗原复合基因－痘苗病毒重组活疫苗株免疫动物后诱发的Th1细胞免疫反应

目的　测定恶性疟原虫-痘苗病毒重组活疫苗候选株免疫动物后产生白细胞介素-2（IL-2）和干扰素（IFN）的生物学活性水平。方法　用MTT法测定了其诱导的保护性细胞免疫反应（Th1细胞免疫反应）。结果　用重组痘苗病毒在免疫家兔及大白鼠4～6wk后血清中IL-2的生物学活性增强,免疫后6wk家兔、大白鼠及小白鼠3种动物血清中IFN的生物学活性水平比免疫前明显升高。结论　恶性疟原虫-痘苗病毒重组活疫苗候选株免疫动物后可诱发机体产生Th1细胞免疫反应。     

重组单纯疱疹病毒-胸苷激酶和人白介素-2基因痘苗病毒真核表达载体的构建

目的 松建含单纯疱疹病毒-胸苷激酶（HSV-tk）和人白介素-2（hIL-2）基因的痘苗病毒真核表达载体pMJ601,为进一步实施胃癌的基因治疗作必要的准备。方法 利用目的的基因与载体的连接、感受态细胞的制备及转化、质粒抽提、琼脂糖凝胶电泳、酶切、DNA序列分析等多种基因工程技术,将纯化回收的HSV-tk和hIL-2分别与pMJ601进行连接、转化并鉴定。结果 分别用BamH I-HindⅢ和Sal I-BamH I酶切位点,将HSV-tk与hIL-2DNA成功地克隆到pMJ601真核表达载体。结论 重组HSV-tk hIL-2基因PMJ601的构建,为进一步研究胃癌的基因治疗打下坚实的基础。     

恶性疟原虫保护性抗原复合基因—痘苗病毒重组活疫苗株家兔免疫血清及IgG对恶性疟原虫的体外抑制试验

用恶性疟原虫痘苗病毒重组活疫苗候选株的家兔免疫血清及纯化的ＩｇＧ 进行了恶性疟原虫的体外培养抑制试验，并与该目的基因的原核表达蛋白及全虫抗原进行了比较。结果在疟原虫的第一个生长周期内，重组痘苗病毒组的免疫血清抑虫作用最强（Ｐ＜ ０．０５），其次为全虫抗原及原核蛋白组；ＩｇＧ 则在第一及第二个生长周期均以原核表达蛋白组抑虫作用最强（ Ｐ＜ ０．０５） ，其次为重组痘苗病毒及全虫抗原组。说明重组痘苗病毒免疫血清及ＩｇＧ具有一定的体外抑制恶性疟原虫增殖作用，值得进一步深入研究。     

PcDNA3/mIL-18对pcDNA3/VP1疫苗免疫效果的影响

目的观察pcDNA3/mIL-18对pcDNA3/VP1DNA疫苗免疫效果的影响。方法从烫伤小鼠肺部组织细胞中提取总RNA进行RT-PCR扩增;将扩增产物与pGEM-T载体连接,构建mIL-18原核表达质粒pGEM-T/mIL-18,酶切纯化mIL-18片断,构建真核表达质粒pcDNA3/mIL-18,将其作为基因佐剂和pcDNA3/VP1共免疫BALB/c小鼠。结果3次免疫后,共免疫组中和抗体滴度高于pcDNA3/VP1组;而病毒滴度低于pcDNA3/VP1组。用10LD50CVB3攻击后,共免疫组小鼠生存率为35%,高于pcDNA3/VP1组。结论PcDNA3/mIL-18对pcDNA3/VP1DNA疫苗的免疫效果有一定的增强作用。     

Generation of Recombinant Rabies Virus CVS-11 Expressing eGFP Applied to the Rapid Virus Neutralization Test

The determination of levels of rabies virus-neutralizing antibody (VNA) provides the foundation for the quantitative evaluation of immunity effects. The traditional fluorescent antibody virus neutralization test (FAVN) using a challenge virus standard (CVS)-11 strain as a detection antigen and staining infected cells with a fluorescein isothiocyanate (FITC)-labeled monoclonal antibody, is expensive and high-quality reagents are often difficult to obtain in developing countries. Indeed, it is essential to establish a rapid, economical, and specific rabies virus neutralization test (VNT). Here, we describe a recombinant virus rCVS-11-eGFP strain that stably expresses enhanced green fluorescent protein (eGFP) based on a reverse genetic system of the CVS-11 strain. Compared to the rCVS-11 strain, the rCVS-11-eGFP strain showed a similar growth property with passaging stability in vitro and pathogenicity in vivo. The rCVS-11-eGFP strain was utilized as a detection antigen to determine the levels of rabies VNAs in 23 human and 29 canine sera; this technique was termed the FAVN-eGFP method. The good reproducibility of FAVN-eGFP was tested with partial serum samples. Neutralization titers obtained from FAVN and FAVN-eGFP were not significantly different. The FAVN-eGFP method allows rapid economical, specific, and high-throughput assessment for the titration of rabies VNAs.     

Characterization of Single-Chain Fv Fragments of Neutralizing Antibodies to Rabies Virus Glycoprotein

Rabies has almost a 100% case-fatality rate and kills more than 59,000 people annually around the world. There is no established treatment for rabies. The rabies virus (RABV) expresses only the glycoprotein (RABVG) at the viral surface, and it is the target for the neutralizing antibodies. We previously established mouse monoclonal antibodies, 15–13 and 12–22, which showed neutralizing activity against the RABV, targeting the sequential and conformational epitopes on the RABVG, respectively. However, the molecular basis for the neutralizing activity of these antibodies is not yet fully understood. In this study, we evaluated the binding characteristics of the Fab fragments of the 15–13 and 12–22 antibodies. The recombinant RABVG protein, in prefusion form for the binding analysis, was prepared by the silkworm–baculovirus expression system. Biolayer interferometry (BLI) analysis indicated that the 15–13 Fab interacts with the RABVG, with a K_D value at the nM level, and that the 12–22 Fab has a weaker binding affinity (K_D ~ μM) with the RABVG compared to the 15–13 Fab. Furthermore, we determined the amino acid sequences of both the antibodies and the designed single-chain Fv fragments (scFvs) of the 15–13 and 12–22 antibodies as another potential biopharmaceutical for targeting rabies. The 15–13 and 12–22 scFvs were successfully prepared by the refolding method and were shown to interact with the RABVG at the nM level and the μM level of the K_D, respectively. These binding characteristics were similar to that of each Fab. On the other hand, differential scanning fluorometry (DSF) revealed that the thermal stability of these scFvs decreases compared to their Fabs. While the improvement of the stability of scFvs will still be required, these results provide insights into the neutralizing activity and the potential therapeutic use of antibody fragments for RABV infection.     

Features of the Antitumor Effect of Vaccinia Virus Lister Strain

Oncolytic abilities of vaccinia virus (VACV) served as a basis for the development of various recombinants for treating cancer; however, “natural” oncolytic properties of the virus are not examined in detail. Our study was conducted to know how the genetically unmodified L-IVP strain of VACV produces its antitumor effect. Human A431 carcinoma xenografts in nude mice and murine Ehrlich carcinoma in C57Bl mice were used as targets for VACV, which was injected intratumorally. A set of virological methods, immunohistochemistry, light and electron microscopy was used in the study. We found that in mice bearing A431 carcinoma, the L-IVP strain was observed in visceral organs within two weeks, but rapidly disappeared from the blood. The L-IVP strain caused decrease of sizes in both tumors, however, in different ways. Direct cell destruction by replicating virus plays a main role in regression of A431 carcinoma xenografts, while in Ehrlich carcinoma, which poorly supported VACV replication, the virus induced decrease of mitoses by pushing tumor cells into S-phase of cell cycle. Our study showed that genetically unmodified VACV possesses at least two mechanisms of antitumor effect: direct destruction of tumor cells and suppression of mitoses in tumor cells.     

Immunogenic potential and protective efficacy of formalin inactivated circulating Indian strain of West Nile virus

Objective:To assess the best suitable condition for virus inactivation.and to study the immunogenic potential and protective efficacy of a circulating West Nile virus(WNV) strain in Assam.Methods:Bulk preparation of circulating WNV:WNIRGC07(GeneBank ID:HQ246154).was undertaken in a bioreaclor using eytodex-1.Virus Inactivation was done in three different conditions:22 ℃.4 ℃ and room temperature.The virus preparations were evaluated for antigenicity by ELISA and toxicity by cell proliferation kit.Virus efficacy was done in-viro on swiss albino mice against standard Indian WNV and Japanese encephalitis virus(JKV)strain.Humoral and cell mediated immune response was evaluated in mice sera by ELISA and neutralization assay.Results:Inactivation at 22 ℃ was found to be more suitable in terms of less toxicity and high antigenicity.The same was selected to study the immune response and efficacy in mice.It induced neutralizing antibody titre of 1:625 and high EgG response.In vivo experiment showed 100% protective efficacy against WNV and 20.8% cross protective efficacy against JEV.Further assessment of cellular immunity through immunized mice revealed augmentation of high levels of pro-inflammatory cytokines and moderate levels of anti—cytokines indicating a mixed balance of Th1 and Th2 response.Conclusions:Findings suggest that formalin inactivated Indian WNV strain has a good immunogenic potential.This is the first study on assessment of immunogenic potential of a lineage 5 strain of WNV.Our study reveals that it would be a promising and effective candidate for vaccine studies which warrants further evaluation.     

Gene Expression Profile Induced by Two Different Variants of Street Rabies Virus in Mice

Pathogenicity and pathology of rabies virus (RABV) varies according to the variant, but the mechanisms are not completely known. In this study, gene expression profile in brains of mice experimentally infected with RABV isolated from a human case of dog rabies (V2) or vampire bat-acquired rabies (V3) were analyzed. In total, 138 array probes associated with 120 genes were expressed differentially between mice inoculated with V2 and sham-inoculated control mice at day 10 post-inoculation. A single probe corresponding to an unannotated gene was identified in V3 versus control mice. Gene ontology (GO) analysis revealed that all of the genes upregulated in mice inoculated with V2 RABV were involved in the biological process of immune defense against pathogens. Although both variants are considered pathogenic, inoculation by the same conditions generated different gene expression results, which is likely due to differences in pathogenesis between the dog and bat RABV variants. This study demonstrated the global gene expression in experimental infection due to V3 wild-type RABV, from the vampire bat Desmodus rotundus, an important source of infection for humans, domestic animals and wildlife in Latin America.     

Preclinical Testing Oncolytic Vaccinia Virus Strain GLV-5b451 Expressing an Anti-VEGF Single-Chain Antibody for Canine Cancer Therapy

Virotherapy on the basis of oncolytic vaccinia virus (VACV) strains is a novel approach for canine cancer therapy. Here we describe, for the first time, the characterization and the use of VACV strain GLV-5b451 expressing the anti-vascular endothelial growth factor (VEGF) single-chain antibody (scAb) GLAF-2 as therapeutic agent against different canine cancers. Cell culture data demonstrated that GLV-5b451 efficiently infected and destroyed all four tested canine cancer cell lines including: mammary carcinoma (MTH52c), mammary adenoma (ZMTH3), prostate carcinoma (CT1258), and soft tissue sarcoma (STSA-1). The GLV-5b451 virus-mediated production of GLAF-2 antibody was observed in all four cancer cell lines. In addition, this antibody specifically recognized canine VEGF. Finally, in canine soft tissue sarcoma (CSTS) xenografted mice, a single systemic administration of GLV-5b451 was found to be safe and led to anti-tumor effects resulting in the significant reduction and substantial long-term inhibition of tumor growth. A CD31-based immuno-staining showed significantly decreased neo-angiogenesis in GLV-5b451-treated tumors compared to the controls. In summary, these findings indicate that GLV-5b451 has potential for use as a therapeutic agent in the treatment of CSTS.     

Development of Monoclonal Antibodies for Detection of Conserved and Variable Epitopes of Large Protein of Rabies Virus

Rabies virus (RABV) causes fatal neurological encephalitis and results in approximately 6000 human death cases worldwide every year. The large (L) protein of RABV, possessing conserved domains, is considered as the target for detection. In this study, three monoclonal antibodies (mAbs), designated as 3F3, 3A6 and L-C, against L protein were generated by using the recombinant truncated L protein (aa 1431–1754) and the epitopes were also identified using a series of overlapping truncated polypeptides for testing the reactivity of mAbs with different RABV strains. The ¹⁴⁷⁹EIFSIP¹⁴⁸⁴, ¹⁶⁵⁹RALSK¹⁶⁶³ and ¹⁷²⁴VFNSL¹⁷²⁸ were identified as the minimal linear epitopes recognized by mAbs 3F3, 3A6 and L-C, respectively. Amino acid alignment showed epitope ¹⁷²⁴VFNSL¹⁷²⁸ recognized by mAb L-C is completely conserved among RABV strains, indicating that mAb L-C could be used to detect all of the RABV strains. Epitope ¹⁴⁷⁹EIFSIP¹⁴⁸⁴ is highly conserved among RABV strains except for a P1484S substitution in a China I sub-lineage strain of Asian lineage, which eliminated the reactivity of the epitope with mAb 3F3. However, the epitope ¹⁶⁵⁹RALSK¹⁶⁶³ was only completely conserved in the Africa-2 and Indian lineages, and a single A1660T substitution, mainly appeared in strains of the China I belonging to Asian lineage and a Cosmopolitan lineage strain, still retained the reactivity of the epitope with mAb 3A6. While both A1660T and K1663R substitutions in a China I lineage strain, single K1663R/Q substitution in some China II strains of Asian lineage and some Arctic-like lineage strains and R1659Q mutation in a strain of Africa-3 lineage eliminated the reactivity of the epitope with mAb 3A6, suggesting mAb 3A6 could be used for differentiation of variable epitopes of some strains in different lineages. Thus, variability and conservation of the three epitopes of L protein showed the reactive difference of mAbs among RABV strains of different lineages. These results may facilitate future studies in development of detection methods for RABV infection, the structure and function of RABV L protein.     

Modified Vaccinia Virus Ankara (MVA) as Production Platform for Vaccines against Influenza and Other Viral Respiratory Diseases

Respiratory viruses infections caused by influenza viruses, human parainfluenza virus (hPIV), respiratory syncytial virus (RSV) and coronaviruses are an eminent threat for public health. Currently, there are no licensed vaccines available for hPIV, RSV and coronaviruses, and the available seasonal influenza vaccines have considerable limitations. With regard to pandemic preparedness, it is important that procedures are in place to respond rapidly and produce tailor made vaccines against these respiratory viruses on short notice. Moreover, especially for influenza there is great need for the development of a universal vaccine that induces broad protective immunity against influenza viruses of various subtypes. Modified Vaccinia Virus Ankara (MVA) is a replication-deficient viral vector that holds great promise as a vaccine platform. MVA can encode one or more foreign antigens and thus functions as a multivalent vaccine. The vector can be used at biosafety level 1, has intrinsic adjuvant capacities and induces humoral and cellular immune responses. However, there are some practical and regulatory issues that need to be addressed in order to develop MVA-based vaccines on short notice at the verge of a pandemic. In this review, we discuss promising novel influenza virus vaccine targets and the use of MVA for vaccine development against various respiratory viruses.     

Point Mutations in the Glycoprotein Ectodomain of Field Rabies Viruses Mediate Cell Culture Adaptation through Improved Virus Release in a Host Cell Dependent and Independent Manner

Molecular details of field rabies virus (RABV) adaptation to cell culture replication are insufficiently understood. A better understanding of adaptation may not only reveal requirements for efficient RABV replication in cell lines, but may also provide novel insights into RABV biology and adaptation-related loss of virulence and pathogenicity. Using two recombinant field rabies virus clones (rRABV Dog and rRABV Fox), we performed virus passages in three different cell lines to identify cell culture adaptive mutations. Ten passages were sufficient for the acquisition of adaptive mutations in the glycoprotein G and in the C-terminus of phosphoprotein P. Apart from the insertion of a glycosylation sequon via the mutation D247N in either virus, both acquired additional and cell line-specific mutations after passages on BHK (K425N) and MDCK-II (R346S or R350G) cells. As determined by virus replication kinetics, complementation, and immunofluorescence analysis, the major bottleneck in cell culture replication was the intracellular accumulation of field virus G protein, which was overcome after the acquisition of the adaptive mutations. Our data indicate that limited release of extracellular infectious virus at the plasma membrane is a defined characteristic of highly virulent field rabies viruses and we hypothesize that the observed suboptimal release of infectious virions is due to the inverse correlation of virus release and virulence in vivo.