Live porcine reproductive and respiratory syndrome virus vaccines: Current status and future direction

Porcine reproductive and respiratory syndrome (PRRS) caused by PRRS virus (PRRSV) was reported in the late 1980s. PRRS still is a huge economic concern to the global pig industry with a current annual loss estimated at one billion US dollars in North America alone. It has been 20 years since the first modified live-attenuated PRRSV vaccine (PRRSV-MLV) became commercially available. PRRSV-MLVs provide homologous protection and help in reducing shedding of heterologous viruses, but they do not completely protect pigs against heterologous field strains. There have been many advances in understanding the biology and ecology of PRRSV; however, the complexities of virus-host interaction and PRRSV vaccinology are not yet completely understood leaving a significant gap for improving breadth of immunity against diverse PRRS isolates. This review provides insights on immunization efforts using infectious PRRSV-based vaccines since the 1990s, beginning with live PRRSV immunization, development and commercialization of PRRSV-MLV, and strategies to overcome the deficiencies of PRRSV-MLV through use of replicating viral vectors expressing multiple PRRSV membrane proteins. Finally, powerful reverse genetics systems (infectious cDNA clones) generated from more than 20 PRRSV isolates of both genotypes 1 and 2 viruses have provided a great resource for exploring many innovative strategies to improve the safety and cross-protective efficacy of live PRRSV vaccines. Examples include vaccines with diminished ability to down-regulate the immune system, positive and negative marker vaccines, multivalent vaccines incorporating antigens from other porcine pathogens, vaccines that carry their own cytokine adjuvants, and chimeric vaccine viruses with the potential for broad cross-protection against heterologous strains. To combat this devastating pig disease in the future, evaluation and commercialization of such improved live PRRSV vaccines is a shared goal among PRRSV researchers, pork producers and biologics companies.     

Vector-based genetically modified vaccines: Exploiting Jenner’s legacy

The global vaccine market is diverse while facing a plethora of novel developments. Genetic modification (GM) techniques facilitate the design of ’smarter’ vaccines. For many of the major infectious diseases of humans, like AIDS and malaria, but also for most human neoplastic disorders, still no vaccines are available. It may be speculated that novel GM technologies will significantly contribute to their development. While a promising number of studies is conducted on GM vaccines and GM vaccine technologies, the contribution of GM technology to newly introduced vaccines on the market is disappointingly limited.In this study, the field of vector-based GM vaccines is explored. Data on currently available, actually applied, and newly developed vectors is retrieved from various sources, synthesised and analysed, in order to provide an overview on the use of vector-based technology in the field of GM vaccine development. While still there are only two vector-based vaccines on the human vaccine market, there is ample activity in the fields of patenting, preclinical research, and different stages of clinical research. Results of this study revealed that vector-based vaccines comprise a significant part of all GM vaccines in the pipeline. This study further highlights that poxviruses and adenoviruses are among the most prominent vectors in GM vaccine development.After the approval of the first vectored human vaccine, based on a flavivirus vector, vaccine vector technology, especially based on poxviruses and adenoviruses, holds great promise for future vaccine development. It may lead to cheaper methods for the production of safe vaccines against diseases for which no or less perfect vaccines exist today, thus catering for an unmet medical need. After the introduction of Jenner’s vaccinia virus as the first vaccine more than two centuries ago, which eventually led to the recent eradication of smallpox, this and other viruses may now be the basis for constructing vectors that may help us control other major scourges of mankind.     

Evaluation of Multicomponent Non-viral Vectors for Liver Directed Gene Delivery

Multicomponent, non-viral gene delivery vehicles are designed to have as a minimum, a DNA binding component, and a cell recognition component for specific delivery to target cells. The DNA binding component cannot only bind, but also protect DNA from serum degradation, and tends to condense DNA to sizes that can be taken up by receptor-mediated processes of target cells. Generally, cationic peptides, single chained, e.g. poly- l -lysine or branched polymers or synthetic peptides with DNA binding properties are used for DNA binding components. Ligands for binding to receptors on cell surfaces can be covalently linked to the DNA binding component. Multicomponent, non-viral vectors have been successfully used to deliver genes into cells in vitro and in vivo. Improvements have been made to the non-viral carriers resulting in increased solubility of DNA/carrier complexes and longer survival in serum. Improvements have also been made by incorporating fusogenic/lysosomolytic components that enable DNA/carrier complexes to escape intracellular degradation and enhance the levels and duration of expression of genes in vitro and in vivo.     

天津市东丽区病媒生物密度调查结果与分析

目的了解天津市东丽区病媒生物的种类及其季节消长规律,为控制病媒生物的危害提供科学依据。方法按照全国病媒生物监测方案设置监测点,分别采用夹夜法、诱蚊灯法、笼诱法、粘捕法调查鼠、蚊、蝇、蜚蠊的种类和密度。结果东丽区优势鼠种为褐家鼠,占捕获总数的79.55%,其次为小家鼠,占20.45%;鼠密度最高峰在8月,次高峰为5月;蚊密度不同生境有所不同,以牲畜棚密度最高,为19.52只/(灯·h),由高到低依次为牲畜棚、农户、公园绿地、医院、居民区;家蝇为优势蝇种,占捕获总数的58.40%,棕尾别麻蝇和市蝇分别占20.41%和7.13%;不同生境捕获数量由高到低依次为餐饮业>农贸市场>居民区>绿化带;蜚蠊优势种为德国小蠊,占捕获总数的99.81%,其密度和侵害率均以农贸市场最高,高峰期为9月。结论调查的各监测点中,餐饮业鼠密度较高,蚊类在牲畜棚密度最高,蝇类在农贸市场密度最高,蜚蠊密度及侵害率均以农贸市场最高,应加强防治。     

Research progress of gene therapy for vascularization of tissue engineering北大核心

BACKGROUND: The rapid formation of functional vascular system in large-scale engineered graft is the basic prerequisite for its successful survival in the host. The vascularization of tissue engineering by genetic engineering technology has the advantages of good therapeutic effect, low cost and high safety. It is of great significance to carry out the research on gene therapy for vascularization of tissue engineering for long-term effective tissue repair. OBJECTIVE: To summarize the current research status and main problems of seed cells, target genes and gene vectors of gene therapy in tissue engineering vascularization so as to further explore the application prospect of gene therapy in tissue engineering vascularization,. METHODS: The literature retrieval was conducted on PubMed, Web of Science, and CNKI with the key words of “tissue engineering; vascularization; gene therapy; seed cells; target genes; vectors” in Chinese and English, and 61 articles closely related to this study were selected for the review. RESULTS AND CONCLUSION: Mesenchymal stem cells, vascular endothelial cells and endothelial progenitor cells are the most potential seed cells for vascularization of tissue engineering using gene therapy. They not only have good vascular induction, but also benefit the introduction of many virus and non-viral vectors and the expression of vascularization target genes. Vascular endothelial growth factor, angiopoietin-1, basic fibroblast growth factor, bone morphogenetic protein-2, hypoxia inducible factor-1 α and other vascularization target genes are mainly used to construct efficient and stable vascular network in engineering grafts by means of combination of double/multiple gene, coupling of osteogenesis and angiogenesis, and regulation of upstream gene. Since different viral and non-viral vectors have their own advantages and disadvantages, suitable vectors should be selected according to the efficiency of gene transfection, biological safety, and cost in application. At present, although great progress has been made in the application of gene therapy in tissue engineering vascularization, there are still many key technologies to be broken through for clinical application, such as how to improve the targeted release of target growth factors and reduce the safety risk, which is also the research direction and hot spot of tissue engineering vascularization based on gene therapy in the future. © 2022, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

构建不同筛选特性的HBV X基因真核表达载体

目的:构建不同筛选特性的两个HBV X基因真核表达载体.方法:从质粒pEcob6中PCR扩增HBV X全基因,利用pCEP4和pcDNA3.1( )两者多克隆位点的特点,选用pGEM(R)-T Easy Vector构建中间载体pEasy-X,分别酶切后连接特异性片段构建载体pCEP4-X和pcDNA3.1( )-X.结果:从质粒pEcob6成功PCR扩增出HBV X全基因并克隆至质粒pEasy-X,酶切、PCR及测序均证实真核表达载体质粒pCEP4-X和pcDNA3.1( )-X构建成功.结论:具有不同筛选特性的两个HBVX基因真核表达载体业已成功构建.     

与细胞脂质蓄积有关的蛋白Adipophilin

动脉粥样硬化性疾病发生发展的关键环节就是单核巨噬细胞和平滑肌细胞脂质的蓄积(包括甘油三酯、胆固醇酯和胆固醇)所导致的泡沫细胞的形成。在泡沫细胞中,这些蓄积的脂质主要以脂滴的形式储存于胞浆中,adipophilin就是脂滴外周含量最高的一种不完全包被蛋白。     

大鼠白细胞介素-10基因全长cDNA的克隆和鉴定

背景：肝纤维化病程迁延且药物治疗效果不理想．基因治疗将成为这一领域研究的热点。研究显示白细胞介素(IL)-10对肝脏具有保护作用，可阻止肝纤维化的发生、发展。目的：克隆并鉴定Sprague-Dawley(SD)大鼠IL-10基因的全长cDNA，为进一步构建大鼠IL-10腺病毒重组子和肝纤维化基因治疗的研究奠定基础。方法：自行设计IL-10上下游引物，以逆转录聚合酶链反应(RT-PCR)从SD大鼠脾脏单核细胞中扩增编码大鼠成熟IL-10肽链的cDNA片断。扩增产物与连接载体pMD-18T连接后转化感受态菌DH5α，构建重组载体pMD-18T-IL-10。结果：以SD大鼠脾脏单核细胞总RNA为模板，RT—PCR扩增出大小为540bp的大鼠IL-10 cDNA片断。所构建的重组质粒经HindⅢ KvnⅠ双酶切显示含有目的基因片段，测序结果证实扩增出的DNA片断与大鼠IL-10基因序列相符，表明编码区无基因突变。结论：成功地克隆了大鼠IL-10基因的全长cDNA，并构建了重组载体pMD-18T-IL-10。     

Gene therapy strategies for the treatment of cancer. A review

This review summarizes current trends in cancer gene therapy. The diversity of approaches and rapid application of technical improvements reflects the interest in this emerging field. Major topics include the restoration of tumor suppressor genes and inhibition of oncogenes, stimulation of the immune response against tumors, and sensitization of cancer cells to systemically administered prodrugs. Special attention is focused on methodstumor targeting and the development of new vectors.