乙型脑炎减毒活疫苗病毒群体的异质性分析

 目的  通过观察疫苗病毒群体中病毒个体的遗传和生物学特征,分析SA14-14-2株乙型脑炎减毒活疫苗病毒的均一性,为疫苗病毒的遗传稳定性提供实验证据。 方法   对3批疫苗病毒连续进行3次蚀斑纯化后,各挑选8个蚀斑纯化株,扩大培养一代。比较24个病毒纯化株的包膜（envelope,E）蛋白基因序列、单斑培养病毒滴度以及蚀斑特征。 结果   24个纯化株中共有6个病毒株（25%）的E蛋白核苷酸发生变化,其中2株（8.3%）的核苷酸变异导致其编码氨基酸发生改变,这些变异占总核苷酸变异数的28.6%。动物实验表明,这2个纯化株没有引起小鼠神经毒力变化。在所有24个纯化株中,我国2010年版药典规定的影响疫苗病毒遗传稳定性的8个E蛋白关键位点的氨基酸均未发生改变。24个纯化株病毒的蚀斑大小和形态以及单斑培养滴度均无明显差异。 结论   疫苗病毒具有典型的准种群体多样性特征,但在群体病毒中未检测到E蛋白氨基酸位点为野生型病毒位点的个体病毒,因此,疫苗病毒具有很好的减毒群体特征和遗传稳定性。     

麻疹腮腺炎风疹联合减毒活疫苗研制

目的 研制中量规模麻疹腮腺炎风疹(measles,mumps and rubella,MMR)联合减毒活疫苗.方法 应用本所自主开发的麻疹病毒纯化沪-191株以及腮腺炎病毒S79株和风疹病毒BRD Ⅱ株制备3种疫苗原液,检测3种疫苗原液按不同比例稀释后病毒的滴度变化和相互之间的干扰现象,确定MMR疫苗中3种疫苗原液的配制比例和半成品配方.产品送国家检定部门进行全面质量检定.观察管制抗生素玻璃瓶包装疫苗的稳定性.结果 3种疫苗原液的病毒滴度在稀释体积增加1倍时下降幅度约为0.35～0.50 lg CCID50/ml,3种病毒之间无明显干扰现象.麻疹、腮腺炎、风疹、稳定剂的配制比例为1∶2∶1∶1.16批中试产品自检、7批产品经国家检定部门检定全部合格,保存21个月稳定性良好.结论 产品全面达到临床前研究的标准.     

肠道病毒71型H6株在Vero细胞上的传代适应及理化特性

目的 研究肠道病毒71型(EV71)在Veto细胞上传代适应的可行性,为用Vero细胞制备EV71疫苗提供科学依据.方法 将EV71 H6株病毒在Veto细胞上进行3次蚀斑筛选并连续传代培养,然后检测适应株的生物学性状及稳定性.结果 经筛选后的Vero细胞适应株可被特异抗EVT1血清中和.传至第5代,病毒滴度可达8.13 LogCCID50/ml.制备毒种的适宜感染剂量(MOI)为0.01,在96 h左右收获的病毒滴度较高.理化学试验结果表明,EV71核酸类型为RNA,不具有耐热性,但可耐受乙醚、酸的作用.结论 EV71 H6株能较好的适应Vero细胞,并保持稳定的生物学性状.     

水痘减毒活疫苗的研制及免疫效果观察

目的    观察由日本大阪大学微生物病研究会(BIKEN)提供的Oka株水痘病毒研制的水痘减毒活疫苗的稳定性、安全性和免疫原性. 方法  按WHO规程要求建立主种子批和工作种子批,检测病毒的生物学特性和疫苗稳定性.在上海市、江苏省进行临床试验,5批疫苗共接种468名2～6岁易感儿童,观察接种者的不良反应,测定抗体阳转率及抗体几何平均滴度.  结果   Oka株水痘病毒在MRC-5细胞上传10代,其生物学特性相似,疫苗在2～8℃保存2年,病毒滴度下降0.3～0.5 lg PFU/剂.易感儿童接种后皮疹发生率为0.21%;低、中、高发热反应率分别为21.79%、10.68%、0.64%.抗体阳转率平均为92.03%. 结论    研制的水痘减毒活疫苗的质量与国外同类产品相似,在易感儿童中的安全性与免疫原性良好,宜推广应用.     

轮状病毒基因重配株Ls(G3型)在Vero细胞上的适应性培养及免疫原性分析

目的:研究轮状病毒基因重配株Ls(G3型)在Vero细胞上的适应性及其免疫原性。方法:将轮状病毒基因重配株Ls(G3型)在Vero细胞上连续传代20代,进行适应培养,通过RNA-PAGE、PCR、核酸电泳、病毒滴度及小鼠免疫试验鉴定其遗传稳定性和免疫原性。结果:筛选出1株Vero细胞适应株(Ls)。该毒株在Vero细胞上稳定传代20代,具有遗传稳定性,且自第5代后病毒滴度均稳定在7.0 lgTCID50.mL-1以上。动物免疫结果表明,Vero细胞适应株Ls诱导小鼠产生高滴度的血清抗体。结论:Ls株可在Vero细胞上稳定增殖,具有遗传稳定性和良好的免疫原性。     

呼吸道合胞病毒疫苗及疫苗研究和开发新方法

呼吸道合胞病毒(respiratory syncytial virus,RSV)是造成婴幼儿、老年人、免疫抑制者等免疫功能低下的人群呼吸道感染的最常见原因之一.RSV是一种单股负链RNA病毒,研究和开发RSV疫苗已有40多年的历史.最初儿童接种福尔马林灭活疫苗后再次感染RSV会出现病情加重的情况;减毒活疫苗在遗传稳定性上存在问题;以纯化的F蛋白和G蛋白研制的部分亚单位疫苗已进入临床试验阶段,尚存在一些需要解决的问题.某些DNA疫苗在动物模型上表现出良好的免疫原性,但由于生物安全的问题,DNA疫苗的应用前景尚不清楚.目前应用反向遗传学技术研制新的BSV疫苗已显示良好的应用前景.     

麻疹、腮腺炎、风疹和水痘联合减毒活疫苗的研制

目的 建立麻疹、腮腺炎、风疹和水痘(measles,mumps,rubella and varicella,MMRV)联合减毒活疫苗的生产工艺和检定方法.方法 采用麻疹病毒沪-191株、腮腺炎病毒S79株、风疹病毒BRDⅡ株、水痘-带状疱疹病毒北京84-7株,在原代鸡胚细胞或人胚肺二倍体细胞2BS株中制备高滴度疫苗病毒原液.观察4种原液按不同比例稀释配制后病毒的滴度变化和相互干扰现象,确定MMRV疫苗中4种原液的配制比例,并筛选适宜保护剂,建立最佳冻干工艺.同时,建立MMRV联合减毒活疫苗的检定方法.采用t检验对结果进行比较.结果 选择最佳配制比例、保护剂和冻干工艺制备出连续多批MMRV疫苗,按国家药典要求检定全部合格.其中连续3批疫苗经国家检定机构检定合格:麻疹病毒基础滴度和37℃放置7d后的滴度分别≥3.9和≥3.5 lg半数细胞培养感染量(50％ cell culture infective dose,CCID50)/ml,腮腺炎病毒≥5.0和≥4.7 lgCCID50/ml,风疹病毒≥5.0和≥4.8 lgCCID50/ml,水痘病毒≥4.5和≥4.4 lg噬斑形成单位/ml.用建立的方法检测MMRV疫苗,结果4种病毒滴度实测值与理论值之间的差异无统计学意义(t值为0.149～1.838,P值均＞0.05).结论 建立了稳定、可行的MMRV疫苗生产工艺和检定方法.     

生产用流感疫苗候选病毒株复制能力的提高

流感疫苗生产主要采用鸡胚病毒培养的方式,而提高流感病毒在鸡胚中的复制能力将能增加疫苗的产量和可靠性.影响病毒在鸡胚中繁殖的重要因素包括:流感病毒血凝素部分位点的氮基酸变异、血凝素与神经氨酸酶之间的作用平衡、病毒其他蛋白的作用及8个基因节段的重配比例.疫苗株制备方法瓶颈的突破和乙型流感病毒重配株的研究也将帮助疫苗生产商选择合适的候选疫苗株.     

生产用流感疫苗候选病毒株复制能力的提高

流感疫苗生产主要采用鸡胚病毒培养的方式,而提高流感病毒在鸡胚中的复制能力将能增加疫苗的产量和可靠性.影响病毒在鸡胚中繁殖的重要因素包括:流感病毒血凝素部分位点的氮基酸变异、血凝素与神经氨酸酶之间的作用平衡、病毒其他蛋白的作用及8个基因节段的重配比例.疫苗株制备方法瓶颈的突破和乙型流感病毒重配株的研究也将帮助疫苗生产商选择合适的候选疫苗株.     

生产用流感疫苗候选病毒株复制能力的提高

流感疫苗生产主要采用鸡胚病毒培养的方式,而提高流感病毒在鸡胚中的复制能力将能增加疫苗的产量和可靠性.影响病毒在鸡胚中繁殖的重要因素包括:流感病毒血凝素部分位点的氮基酸变异、血凝素与神经氨酸酶之间的作用平衡、病毒其他蛋白的作用及8个基因节段的重配比例.疫苗株制备方法瓶颈的突破和乙型流感病毒重配株的研究也将帮助疫苗生产商选择合适的候选疫苗株.     

Optimized development of a candidate strain of inactivated EV71 vaccine and analysis of its immunogenicity in rhesus monkeys

Enterovirus type 71 (EV71) is one of the main etiologic agents responsible for periodic epidemics of hand-foot-and-mouth disease (HFMD). The prevention and control of EV71 epidemics with effective anti-viral agents and vaccines is very important for public health. Because the pathogenesis of EV71 in the human body is not completely clear and genetic variations in the virus during its replication are difficult to control, we have focused on the development of an inactivated whole-virus vaccine. In this study, we screened 16 strains isolated from different areas of China and selected one strain for the development of an inactivated EV71 vaccine. The results of our study suggest that the FY-23K-B strain, which is a candidate strain for an EV71 inactivated vaccine, satisfied the requirements of vaccine production in terms of genetic stability, biological activity, and good immunogenicity. The experimentally inactivated vaccine produced using this strain was capable of inducing an immune response and offered protection to rhesus monkeys against future virus attacks.     

Nucleic acid for the treatment of cancer: genetic vaccines and DNA adjuvants

Despite some interesting pilot experiments more than a century ago, nucleic acid has only recently been added to the list of agents used for the prevention and therapy of cancer. Two distinct features of nucleic acids are used for this purpose: in DNA and RNA vaccines, genetic information for pathogen- or tumor-derived antigens is delivered to the host who then produces the encoded antigen and initiates an immune response. In DNA adjuvants, immunostimulatory sequences (CpG motifs) present in DNA of bacterial origin are used. Such sequences are delivered in the form of oligonucleotides or within the sequence of DNA vaccine. In addition, CpG oligonucleotides by themselves have successfully been used to stimulate the immune system in an antigen-independent manner for the treatment of experimental tumors. DNA and RNA vaccines for the treatment and prevention of cancer and other diseases suffer from two some shortcomings: insufficient immunogenicity and--in the case of RNA--low stability. A variety of strategies are being explored to improve the efficacy of nucleic acid vaccines (genetic vaccines) especially for self-antigens in the case of cancer. Among the most recent improvements are self-replicating RNA vaccines and replicase-based DNA-vaccines in which antigen expression is under the control of an alphaviral replicase. Despite highly promising results in many animal tumor models the efficacy of nucleic acid vaccines and adjuvants in the clinic remains to be seen.     

流感病毒裂解疫苗及单价病毒液的血凝素稳定性研究

目的 通过对连续三年生产的流行性感冒(流感)病毒裂解疫苗成品和单价病毒液(MVP)血凝素(HA)的定期检测,了解成品和MVP的HA含量的变化情况,以便更准确、有效地配制半成品.  方法 2003-2005年,每年选择一定数量的成品和MVP,按一定时间间隔抽样,采用单向免疫扩散法检测成品和MVP的HA含量.观察期至少为1年.  结果 成品存放至半年,HA含量都在控制范围之内.但存放至1年,个别毒株HA含量降至低于控制范围.MVP的HA稳定性因毒株的不同而异.   结论 一般情况下,流感疫苗在成品检定合格后7个月内完成使用,因此,在此期间,成品的HA含量在合格范围之内.不同毒株的MVP,HA降幅不同,可能是由于编码HA蛋白的RNA4节段的核苷酸序列在不同亚型,甚至在同一亚型不同变异株间的差异所造成的.     

Towards an epitope-based human vaccine for influenza

The conventional, currently available vaccines against influenza virus, though quite successful, suffer from a few shortcomings; one major limitation is their restriction to the specific strains that are included in the vaccine. We review herewith some of the more recently developed influenza vaccines and further describe our own results on the design of epitope-based vaccine for human use. In this vaccine, a combination of B- and T-cell epitopes are individually expressed within an immunogenic molecule--salmonella flagellin--and the resultant recombinant flagella serve both as a carrier and as an adjuvant. The mixture of recombinant flagella expressing the appropriate epitopes was administered to young and aged mice as well as to human/mouse chimera model in which human PBMC are functioning within the mice body. Intranasal immunization in all these animal models led to effective protection against challenge infection with different strains of influenza virus.     

Influenza vaccines: new developments

Current inactivated influenza vaccines are being produced with three influenza virus strains that are recommended annually by the World Health Organization on the basis of information obtained from global influenza surveillance. The use of these vaccines, for which the antigens are produced in embryonated chicken eggs, can result in a significant reduction of influenza-related morbidity and mortality. Nevertheless, there is still a demand for vaccines with a higher efficacy that can be produced more rapidly and more flexibly in response to an epidemic or a pandemic. New developments in the field of influenza vaccine preparation include novel vaccine production technologies, reverse genetics technology for the generation of vaccine strains and novel adjuvants for the improvement of vaccine immunogenicity.     

Addressing the Cold Reality of mRNA Vaccine Stability

As mRNA vaccines became the frontrunners in late-stage clinical trials to fight the COVID-19 pandemic, challenges surrounding their formulation and stability became readily apparent. In this commentary, we first describe company proposals, based on available public information, for the (frozen) storage of mRNA vaccine drug products across the vaccine supply chain. We then review the literature on the pharmaceutical stability of mRNA vaccine candidates, including attempts to improve their stability, analytical techniques to monitor their stability, and regulatory guidelines covering product characterization and storage stability. We conclude that systematic approaches to identify the key physicochemical degradation mechanism(s) of formulated mRNA vaccine candidates are currently lacking. Rational design of optimally stabilized mRNA vaccine formulations during storage, transport, and administration at refrigerated or ambient temperatures should thus have top priority in the pharmaceutical development community. In addition to evidence of human immunogenicity against multiple viral pathogens, including compelling efficacy results against COVID-19, another key strength of the mRNA vaccine approach is that it is readily adaptable to rapidly address future outbreaks of new emerging infectious diseases. Consequently, we should not wait for the next pandemic to address and solve the challenges associated with the stability and storage of formulated mRNA vaccines.     

DNA-based influenza vaccines: evaluating their potential to provide universal protection

The recent outbreaks of the H5N1 and H1N1 pandemic influenza have highlighted the importance of developing fast, effective therapeutic strategies to prevent and/or limit the spread of future influenza outbreaks. Although current vaccines against influenza are generally effective, several limitations, including those associated with the amount of available vaccine, the time to vaccine production and vaccine efficacy, may encumber a mass vaccination strategy and effective targeting against future outbreaks. This feature review discusses the prospects of SynCon-derived DNA vaccines against influenza; such vaccines are expected to be effective at targeting many currently circulating influenza virus strains, as well as potentially targeting strains that may be associated with future outbreaks. Because of advantages associated with safety, time to production and ease of production, as well as the generation of more effective immune responses, influenza DNA vaccines provide a promising potential solution to a global medical concern.     

A/H5N1 prepandemic influenza vaccine (whole virion, vero cell-derived, inactivated) [Vepacel®

The influenza A subtype H5N1 virus is a likely causative agent for the next human influenza pandemic. Pandemic influenza vaccine production can begin only after a novel pandemic virus emerges. Cell-based vaccine production has advantages over conventional egg-based methods, allowing more rapid large-scale vaccine production. A reliable Vero cell culture system is available for pandemic and prepandemic influenza vaccine production. Prepandemic influenza vaccines are an important component of influenza pandemic preparedness plans, as their targeted use in the pandemic alert period or early in a pandemic is likely to mitigate the consequences of an influenza outbreak. Vepacel? is a prepandemic influenza vaccine (whole virion, Vero cell-derived, inactivated) containing antigen of H5N1 strain A/Vietnam/1203/2004 and is approved for use in the EU. Clinical immunogenicity studies with the vaccine have demonstrated good rates of functional neutralizing antibody responses against the vaccine strain (A/Vietnam/1203/2004), meeting established immunogenicity criteria for seasonal influenza vaccines, and cross-reactivity against H5N1 strains from other clades. In phase I/II and III studies, a heterologous (A/Indonesia/05/2005) booster vaccine administered to healthy adult and elderly volunteers 6-24 months after the two-dose priming vaccine (A/Vietnam/1203/2004) regimen induced good immunogenic responses against both H5N1 strains, demonstrating strong immunological memory. Broadly similar, albeit less robust, responses were observed in two special risk cohorts of immunocompromised and chronically ill patients. In general, adverse events observed in clinical immunogenicity studies with H5N1 vaccine (A/Vietnam/1203/2004) were similar to those reported with non-adjuvanted, inactivated, seasonal influenza vaccines.