Freeze-Drying Formulations Increased the Adenovirus and Poxvirus Vaccine Storage Times and Antigen Stabilities

Successful vaccines induce specific immune responses and protect against various viral and bacterial infections. Noninactivated vaccines, especially viral vector vaccines such as adenovirus and poxvirus vaccines, dominate the vaccine market because their viral particles are able to replicate and proliferate in vivo and produce lasting immunity in a manner similar to natural infection. One challenge of human and livestock vaccination is vaccine stability related to the antigenicity and infectivity. Freeze-drying is the typical method to maintain virus vaccine stability, while cold chain transportation is required for temperatures about 2 °C–8 °C. The financial and technological resource requirements hinder vaccine distribution in underdeveloped areas. In this study, we developed a freeze-drying formula consisting of bovine serum albumin(BSA), L-glutamic acid(L-Glu), polyethylene glycol(PEG), and dextran(DEX) to improve the thermal stability and activity of viral vaccines, including vaccinia recombinant vaccine(rTTV-OVA) and adenovirus vaccine(Ad5-ENV). We compared a panel of five different formulations(PEG: DEX: BSA: L-GLU = 50:9:0:0(#1), 50:5:4:0(#2), 50:10:9:0(#3),50:0:0:9(#4), and 50:1:0:8(#5), respectively) and optimized the freeze-drying formula for rTTV-OVA and Ad5-ENV. We found that the freeze-drying formulations #2 and #3 could maintain rTTV-OVA infectivity at temperatures of 4 °C and25 °C and that r TTV-OVA immunogenicity was retained during lyophilization. However, formulations #4 and #5 maintained Ad5-ENV infectivity under the same conditions, and Ad5-ENV immunogenicity had maximum retention with freeze-drying formulation #4. In summary, we developed new freeze-drying formulations that increased virus vaccine storage times and retained immunogenicity at an ambient temperature.     

Mitigating the looming vaccine crisis: production and delivery of plasmid-based vaccines

The exponentially growing human population and the emergence of new diseases are clear indications that the world can no longer depend solely on conventional vaccine technologies and production schemes. The race to find a new vaccine technology is crucial to help speed up and complement the World Health Organization (WHO) disease elimination program. The ultimate goal is to uncover fast and efficient production schemes in the event of a pandemic, and also to effectively fight deadly diseases such as malaria, bird flu, hepatitis, and human immunodeficiency virus (HIV). Plasmid DNA vaccines, if properly formulated, offer specific priming of the immune system and similar or even better prophylactic effects than conventional vaccines. This article discusses many of the critical issues that need to be considered when developing fast, effective, and reliable plasmid DNA vaccine manufacturing processes. Different modes of plasmid production via bacterial fermentation are compared. Plasmid purification by chromatography is specifically discussed as it is the most commercially viable bioprocess engineering technique for continuous purification of supercoiled plasmid DNA. Current techniques and progress covering the area of plasmid DNA vaccine design, formulation, and delivery are also put forward.     

A、B、C三型流感病毒病毒学、流行病学、临床特征和流感疫苗

２０世纪人类遭受了４次流感大流行,数千万人失去了生命,流感病毒分Ａ、Ｂ、Ｃ三型,对其病毒学、流行病学和临床特征,以及流感病毒传统疫苗－－灭活疫苗和新型疫苗－－核酸疫苗的研究进展作了论述。     

DNA疫苗预防B型流感病毒感染

用基因枪和电穿孔法将B型流感病毒DNA疫苗免疫BALB/C小鼠 ,实验证明B型流感病毒HA ,NADNA疫苗能有效抵御致死性同源B型病毒感染。同时实验表明 ,基因枪方法较电穿孔法诱导抗体水平略低。     

DNA Gyrase: Structure and Function

Abstract

DNA gyrase is an essential bacterial enzyme that catalyzes the ATP-dependent negative super-coiling of double-stranded closed-circular DNA. Gyrase belongs to a class of enzymes known as topoisomerases that are involved in the control of topological transitions of DNA. The mechanism by which gyrase is able to influence the topological state of DNA molecules is of inherent interest from an enzymological standpoint. In addition, much attention has been focused on DNA gyrase as the intracellular target of a number of antibacterial agents and as a paradigm for other DNA topoisomerases. In this review we summarize the current knowledge concerning DNA gyrase by addressing a wide range of aspects of the study of this enzyme.     

Augmentation of antigen-specific immune responses using DNA-fusogenic liposome vaccine

In an attempt to enhance the immunological efficacy of genetic immunization, we investigated a new biological means for delivering antigen gene directly to the cytoplasm via membrane fusion. In this context, we investigated fusogenic liposome (FL) encapsulating DNA as a possible genetic immunization vehicle. RT-PCR analysis indicated that a FL could introduce and express encapsulating OVA gene efficiently and rapidly in vitro. Consistent with this observation, an in vitro assay showed that FL-mediated antigen-gene delivery can induce potent presentation of antigen via the MHC class I-dependent pathway. Accordingly, immunization with FL containing the OVA-gene induced potent OVA-specific Th1 and Th2 cytokine production. Additionally, OVA-specific CTL responses and antibody production were also observed in systemic compartments including the spleen, upon immunization with the OVA-gene encapsulating FL. These findings suggest that FL is an effective genetic immunization carrier system for the stimulation of antigen-specific immune responses against its encoding antigen.     

A型流感病毒血凝素、神经氨酸酶DNA疫苗研究

用BALB/C小鼠为模型,检测A型流感病毒血凝素、神经氨酸酶、基质蛋白DNA疫苗抗流感能力。研究表明:血凝素、神经氨酸酶DNA疫苗能提供有效的抗流感保护;血凝素、神经氨酸酶和基质蛋白联合免疫动物提供最佳免疫保护。     

Structure and Function of RecQ DNA Helicases

RecQ family helicases play important roles in coordinating genome maintenance pathways in living cells. In the absence of functional RecQ proteins, cells exhibit a variety of phenotypes, including increased mitotic recombination, elevated chromosome missegregation, hypersensitivity to DNA-damaging agents, and defects in meiosis. Mutations in three of the five human RecQ family members give rise to genetic disorders associated with a predisposition to cancer and premature aging, highlighting the importance of RecQ proteins and their cellular activities for human health. Current evidence suggests that RecQ proteins act at multiple steps in DNA replication, including stabilization of replication forks and removal of DNA recombination intermediates, in order to maintain genome integrity. The cellular basis of RecQ helicase function may be explained through interactions with multiple components of the DNA replication and recombination machinery. This review focuses on biochemical and structural aspects of the RecQ helicases and how these features relate to their known cellular function, specifically in preventing excessive recombination.     

皱边石杉基因组总DNA保存期间的质量检测分析

目的:用CTAB法提取皱边石杉叶片的基因组总DNA,对DNA储存于4℃的TE缓冲溶液与65℃水浴促溶2种实验处理进行为期30d的稳定性对比实验。方法:对比分析保存于4℃的TE缓冲溶液中与65℃进行2～3次水浴促进DNA溶解释放处理的DNA的稳定性及完整性变化。结果:保存于4℃TE缓冲溶液中的DNA样品非常稳定;65℃水浴促进了DNA从包裹的多糖中溶解释放,但2～3次水浴使大片段的DNA降解。结论:DNA保存在TE缓冲溶液中非常稳定;65℃水浴尽管可提高DNA的提取量,但会使DNA发生降解。因此,一般情况下对DNA不要进行水浴促溶。     

禽流感病毒HA基因真核表达质粒的构建与表达

血凝素蛋白（HA）基因是禽流感病毒（AIV）重要的保护性抗原基因.为了研究 HA基因疫苗,用PCR扩增H5亚型AIV HA基因,将其克隆到质粒pcDNA4/HisMax和pRc/CMV上得到真核表达质粒pC4H5和pCMVH5.采用Tfx^TM-20、Superfect转染试剂和电转染法转染HeLa细胞,转染后的HeLa细胞经蛋白质印迹和血凝试验检测HA蛋白及其活性.结果表明,Superfect转染和电转染均能正确表达HA蛋白并具有生物学活性,蛋白质印迹检测到HA和HA裂解的HA1和HA2,与AIV 的HA、HA1、HA2蛋白的分子质量一致.从血凝试验结果看,Superfect和电转染表达的HA均具有血凝活性,而经Superfect转染的pC4H5的表达量是pCMVH5的8倍,表明pC4H5是一高效的真核表达质粒.     

A、B型流感病毒HA1嵌合基因疫苗的构建及免疫保护研究

为制备能提供交叉保护的疫苗,本研究在证实A型、B型流感病毒HA1 DNA能够提供抗流感病毒保护的基础上,将编码A型和B型流感病毒HA1的基因构建在同一质粒中,制备成嵌合DNA疫苗.将该重组质粒免疫小鼠,并以致死量同种流感病毒A/PR/8/34或B/Ibaraki/2/85攻击,通过测定小鼠的血清抗HA抗体和保护效果(包括存活率、肺部病毒量和体重丢失率)来评价DNA疫苗的免疫效果.结果表明:A、B型流感病毒HAl嵌合DNA疫苗能保护小鼠抵抗两种致死量流感病毒的攻击,具有提供交叉保护的能力.     

通用型流感疫苗的研究现状与展望

接种流感疫苗是预防和控制流感最为有效的措施。流感病毒由于其宿主多样、亚型众多,流感疫苗的有效性十分受限,同时由于其具有高度的变异性,一旦有较大的变异或新亚型的流感病毒出现,现有疫苗就会失效,因此研制能够通过免疫交叉反应对变异较大或多种亚型的流感病毒提供广泛保护的通用型流感疫苗迫在眉睫。     

Intranasal immunization with chitosan microparticles enhances LACK-DNA vaccine protection and induces specific long-lasting immunity against visceral leishmaniasis

Development of a protective vaccine against Leishmania depends on antigen formulation and adjuvants that induce specific immunity and long-lasting immune responses. We previously demonstrated that BALB/c mice intranasally vaccinated with a plasmid DNA encoding the p36/LACK leishmanial antigen (LACK-DNA) develop a protective immunity for up to 3 months after vaccination, which was linked with the systemic expression of vaccine mRNA in peripheral organs. In this study, LACK-DNA vaccine was associated with biocompatible chitosan microparticles cross-linked with glyceraldehyde (CMC) to boost the long-lasting immunity against the late Leishmania infantum challenge. Infection at 7 days, 3 or 6 months after vaccination resulted in significantly lower parasite loads when compared with non-vaccinated controls. Besides, LACK-DNA-chitosan vaccinated mice showed long-time protection observed after the late time point challenge. The achieved protection was correlated with an enhanced spleen cell responsiveness to parasite antigens, marked by increased proliferation and IFN-γ as well as decreased IL-10 production. Moreover, we found diminished systemic levels of TNF-α that was compatible with the better health condition observed in LACK-DNA/CMC vaccinated-infected mice. Together, our data indicate the feasibility of chitosan microparticles as a delivery system tool to extend the protective immunity conferred by LACK-DNA vaccine, which may be explored in vaccine formulations against Leishmania parasite infections.     

DNA光解酶的结构与功能研究进展

对近年来在包括酶蛋白、辅酶的DNA光解酶结构及其与功能关系方面的研究进展作了综述.DNA光解酶可通过光诱导的电子转移催化裂解环丁烷嘧啶二聚体(Pyr<>Pyr),从而修复紫外线引起的DNA的主要损伤.研究发现,来自不同有机体的光解酶均含有两个非共价的辅基一个是1,5-二氢黄素腺嘌呤二核苷酸(FADH2),另一个是次甲基四氢叶酸(MTHF)或8-羟基-5-去氮杂核黄素(8-HDF),前者具有催化活性,可在光作用下通过电子转移裂解嘧啶二聚体,后者不具有催化活性,但能收集光子并将能量传递给FADH2,具有“天线”作用.     

IL-12增强流感血凝素DNA疫苗在小鼠中抗流感作用

流感病毒的表面抗原血凝素 (hemagglutinin ,HA)能作为DNA疫苗抗流感病毒攻击 ,在小鼠模型中检测白介素 12 (interleukin 12 ,IL 12 )能否作为HADNA疫苗佐剂增强小鼠抗流感病毒攻击。将IL 12和HA共同免疫小鼠 ,免疫 2次 ,间隔 3周 ,加强免疫后用致死量流感病毒攻击。共同免疫IL 12和HADNA与单独免疫HA相比 ,无论初免还是加强免疫后血清中抗HA的IgG抗体显著提高 ,小鼠体重丢失 (一种临床症状 )明显减少且提高了小鼠的存活率。这些结果表明了IL 12能作为一种佐剂提高流感DNA疫苗的免疫效价。     

Noncryogenic Preservation of Mammalian Tissues for DNA Extraction: An Assessment of Storage Methods

Reliable field methods for the storage of tissues to be used for DNA extraction and amplification are critical to many studies employing molecular techniques. Protection from DNA degradation was compared among three commonly used methods of noncryogenic storage of tissues over a time scale of 2 years. All three methods prevented DNA degradation during storage for at least 6 months. DMSO (dimethyl sulfoxide)-salt solution provided the best protection from DNA degradation of tissues stored for up to 2 years. High molecular weight DNA was recovered from lysis buffer in which tissue was stored for 2 years, however, moderate amounts of degraded DNA was also present. High molecular weight DNA was recovered from tissues stored in ethanol for 2 years, however, the yield was relatively small compared to the other two noncryogenic storage techniques. Much of the DNA degradation in ethanol preserved tissues appeared to occur during the extraction procedure and can be reduced by soaking the tissue in lysis buffer for a few hours prior to beginning the extraction. The yield of PCR products was greatest from DNA extracted from DMSO-salt solution preserved tissues, whereas DNA from tissues stored in either lysis buffer or ethanol produced lower yields.     

一次接种HA DNA保护小鼠抵抗B型流感病毒攻击

为详细探讨小鼠不同次数接种B型流感病毒HA DNA疫苗后免疫应答情况,以及CpG基序的免疫佐剂效果,采用不同剂量HA DNA,1次或2次(间隔3周)电击法免疫BALB/C小鼠。初免4周后(或二免加强免疫1周后)用致死量流感病毒(B/Ibaraki/2/85)攻击。研究发现:①100μg HA DNA一次接种的小鼠全部存活;②经含有CpG基序的DNA免疫的小鼠体内诱导产生的抗HAIgG抗体更高,小鼠体重丢失更少。这些结果说明,1次接种100μg HA DNA疫苗可以使小鼠抵抗致死量B型流感病毒攻击,CpG基序能够增强HA DNA疫苗的免疫保护作用。     

Structure,Function, and Mechanism of HhaI DNA Methyltransferases

A vast amount of literature has accumulated on the characterization of DNA methyltransferases. The HhaI DNA methyltransferase, a C5-cytosine methyltransferase, has been the subject of investigation for the last 2 decades. Biochemical and kinetic characterization have led to an understanding of the catalytic and kinetic mechanism of the methyltransfer reaction. The HhaI methyltransferase has also been subjected to extensive structural analysis, with the availability of 12 structures with or without a cofactor and a variety of DNA substrates. The mechanism of base flipping, first described for the HhaI methyltransferase, is conserved among all DNA methyltransferases and is also found to occur in numerous DNA repair enzymes. Studies with other methyltransferase reveal a significant structural and functional similarity among different types of methyltransferases. This review aims to summarize the available information on the HhaI DNA methyltransferase.     

Preservation of Bone Structure and Function by Lithothamnion sp. Derived Minerals

Progressive bone mineral loss and increasing bone fragility are hallmarks of osteoporosis. A combination of minerals isolated from the red marine algae, Lithothamnion sp. was examined for ability to inhibit bone mineral loss in female mice maintained on either a standard rodent chow (control) diet or a high-fat western diet (HFWD) for 5, 12, and 18 months. At each time point, femora were subjected to μ-CT analysis and biomechanical testing. A subset of caudal vertebrae was also analyzed. Following this, individual elements were assessed in bones. Serum levels of the 5b isoform of tartrate-resistant acid phosphatase (TRAP) and procollagen type I propeptide (P1NP) were also measured. Trabecular bone loss occurred in both diets (evident as early as 5 months). Cortical bone increased through month 5 and then declined. Cortical bone loss was primarily in mice on the HFWD. Inclusion of the minerals in the diet reduced bone mineral loss in both diets and improved bone strength. Bone mineral density was also enhanced by these minerals. Of several cationic minerals known to be important to bone health, only strontium was significantly increased in bone tissue from animals fed the mineral diets, but the increase was large (5–10 fold). Serum levels of TRAP were consistently higher in mice receiving the minerals, but levels of P1NP were not. These data suggest that trace minerals derived from marine red algae may be used to prevent progressive bone mineral loss in conjunction with calcium. Mineral supplementation could find use as part of an osteoporosis-prevention strategy.     

用电穿孔方法研究 H5N1 禽流感病毒DNA 疫苗对动物的免疫保护作用

为了研究 H5N1 DNA 疫苗对小鼠和鸡的保护效率,用 H5N1 禽流感病毒 HA DNA 疫苗免疫 BALB/c 小鼠和 SPF 鸡 . 小鼠和鸡分别经电穿孔和肌肉注射免疫两次,间隔为 3 周 . 二次免疫后,用致死量的同源病毒进行攻毒实验 . 空白对照组在攻毒后全部死亡,而经电穿孔免疫的小鼠和鸡均获得了完全的保护,并能有效地抑制病毒在小鼠肺脏和鸡泄殖腔的繁殖 . 同时,电穿孔免疫的小鼠和鸡均产生了高水平的特异性抗体 . 经电穿孔免疫的小鼠攻毒后 CTL 反应明显加强 . 这些结果表明, HA DNA 疫苗能有效地保护小鼠和鸡对禽流感病毒的感染,同时也表明电穿孔免疫是 DNA 疫苗免疫的有效途径之一 .