Advances in hepatitis C virus vaccines,part two: advances in hepatitis C virus vaccine formulations and modalities

Introduction: Developing a vaccine against HCV is an important medical and global priority. Unavailability and potential dangers associated with using attenuated HCV viral particles for vaccine preparation have resulted in the use of HCV genes and proteins formulated in novel vaccine modalities.

Areas covered: In part one of this review, advances in basic knowledge for HCV vaccine design were provided. Herein, a detailed and correlated patents (searched by Espacenet) and literatures (searched by Pubmed) review on HCV vaccine formulations and modalities is provided, including: subunit, DNA, epitopic-peptide/polytopic, live vector- and whole yeast-based vaccines. Less-touched areas in vaccine studies such as mucosal, plant-based, and chimeric HBV/HCV vaccines are also discussed. Furthermore, results of preclinical/clinical studies on selected HCV vaccines as well as pros and cons of different strategies are reviewed. Finally, potential strategies for creation and/or improvement of HCV vaccine formulations are discussed.

Expert opinion: Promising outcomes of a few HCV vaccine modalities in phase I/II clinical trials predict the accessibility of at least partially effective vaccines to inhibit or treat the chronic state of HCV infection (specially in combination with standard antiviral therapy). ChronVac-C (plasmid DNA), TG4040 (MVA-based), and GI-5005 (whole yeast-based) might be the most obvious HCV vaccine candidates to be approved in the near future.     

Gene transfer by viral vectors for gene therapy

Conclusions The search for useful virus vectors and for improvements in currently available retrovectors which may have the capability of transportation by natural transport systems in the human body will open effective ways for targeting human genes to specific cells in tissues in situ. Genetic engineering of virus vectors is a subject of prime importance to the developing gene therapy protocols in humans.Abbreviations HSV Herpes simplex virus     

国境口岸医学媒介生物监测与可持续控制策略的探讨

为了进一步强化医学媒介生物监测和防治工作,本文从国境口岸医学媒介生物监测与控制工作现状入手,对国境口岸医学媒介生物监测与可持续控制策略进行了探讨,为制订医学媒介生物防治方案提供依据,并在工作中逐步细化、丰富、完善相关工作。     

Viral vectors in malaria vaccine development

Traditional vaccine technologies have resulted in an impressive array of efficacious vaccines against a variety of infectious agents. However, several potentially deadly pathogens, including retroviruses and parasites, have proven less amenable to the application of traditional vaccine platforms, indicating the need for new approaches. Viral vectors represent an attractive way to deliver and present vaccine antigens that may offer advantages over traditional platforms. Due to their ability to induce strong cell-mediated immunity (CMI) in addition to antibodies, viral vectors may be suitable for infectious agents, such as malaria parasites, where potent CMI is required for protection. Poxvirus-vectored malaria vaccines have been the most extensively studied in the clinic, achieving significant reductions in liver-stage parasite burden. More recently, adenovirus-vectored malaria vaccines have entered clinical testing. The most promising approach – heterologous prime-boost regimens, in which different viral vectors are sequentially paired with each other or with DNA or recombinant protein vaccines – is now being explored, and could provide high-grade protection, if findings in animal models are translatable to humans. Significant barriers remain, however, such as pre-existing immunity to the vector particle and an unexplained safety signal observed in one trial suggesting an increased risk of HIV acquisition in volunteers with pre-existing immunity to the vector.     

肝细胞移植临床前研究：大鼠肝细胞分离,培养和逆转录病毒转导

目的建立完善的肝细胞培养系统，研究逆转录病毒载体转移并表达于大鼠原代肝细胞。方法采用表皮生长因子（ＥＧＦ）刺激大鼠原代肝细胞增殖，以表达β－半乳糖苷酶的双顺反子逆转录病毒载体（ｐＧＣＥＮ／β－ｇａｌ）感染肝细胞。Ｘ－ｇａｌ原位染色方法检测肝细胞内ＬａｃＺ的表达，采用ＰＣＲ方法扩增ＮｅｏＲ基因，从ＤＮＡ水平证实逆转录病毒载体整合入肝细胞。结果ＥＧＦ在体外可刺激肝细胞增殖并维持肝细胞功能，肝细胞表达β－半乳糖苷酶基因，肝细胞中可扩增出ＮｅｏＲ基因片断。结论双顺反子逆转录病毒载体可有效介导β－ｇａｌ和ＮｅｏＲ基因表达于大鼠肝细胞，提示可用于标记原代大鼠肝细胞，有利于研究肝细胞移植后移植之肝细胞在体内的寿命、分布及功能。     

肿瘤坏死因子受体2编码基因重组质粒的构建及意义

目的构建真核表达质粒pcDNA6.0-TNFR2~196MET和pcDNA6.0-TNFR2~196ARG。方法人工合成TNFR2~196MET目的片段,与pMD18-Tsimple载体连接形成克隆载体,再通过设计突变引物,PCR定点突变扩增出含有突变位点的质粒,转化到肠埃希菌感受态细胞JM109中,通过氨苄青霉素抗药性筛选出成功转化的阳性克隆,并进行扩增。抽提质粒进行测序鉴定,得到pMD18-Tsimple-TNFR2196ARG。双酶切pMD18-Tsimple-TN-FR2196MET、pMD18-Tsimple-TNFR2196ARG及pcDNA6.0,将TNFR2196MET、TNFR2196ARG插入pcDNA6.0线性质粒,即构建成pcDNA6.0-TNFR2196MET和pcDNA6.0-TNFR2196ARG真核表达质粒,转化到Ecoli感受态中,筛选阳性克隆行菌液PCR和双酶切及测序鉴定。结果酶切鉴定和测序分析验证TNFR2基因196MET和196ARG表达载体构建成功。结论成功构建表达载体为下一步心血管疾病研究奠定了实验基础。     

New therapeutic opportunities for hepatitis C based on small RNA

Hepatitis C virus (HCV) infection is one of the major causes of chronic liver disease, including cirrhosis and liver cancer and is therefore, the most common indication for liver transplantation. Conventional antiviral drugs such as pegylated interferon-alpha, taken in combination with ribavirin, represent a milestone in the therapy of this disease. However, due to different viral and host factors, clinical success can be achieved only in approximately half of patients, making urgent the requirement of exploiting alternative approaches for HCV therapy. Fortunately, recent advances in the understanding of HCV viral replication and host cell interactions have opened new possibilities for therapeutic intervention. The most recent technologies, such as small interference RNA mediated gene-silencing, anti-sense oligonucleotides (ASO), or viral vector based gene delivery systems, have paved the way to develop novel therapeutic modalities for HCV. In this review, we outline the application of these technologies in the context of HCV therapy. In particular, we will focus on the newly defined role of cellular microRNA (miR-122) in viral replication and discuss its potential for HCV molecular therapy.     

Instructive cross-talk between neural progenitor cells and gliomas

Gliomas are the most common primary brain tumors and offer a poor prognosis in patients because of their infiltrative and treatment-resistant nature. The median survival time after diagnosis is approximately 11-12 months. There is a strong need for novel treatment modalities in targeting gliomas, and recent advances use neural progenitor cells as delivery systems for different therapeutic strategies. In this study, we show that rat embryonic neural progenitor cell (NPC) lines, transplanted at a distant site from a 3-day-preestablished glioma in the striatum, were able to migrate toward and colocalize with tumor isles without general spread into the brain parenchyma. Upon encounter with tumor, neural progenitor cells changed phenotype and became vimentin positive. These results demonstrate that transplanted neural progenitor cells respond to queues from a tumor and home to and exert an antitumor effect on the preestablished glioma, significantly decreasing the tumor volume with approximately 67% compared with control tumors after 1-2 weeks. Moreover, these early effects could be translated into increased survival times of animals treated with neural progenitor cell grafts 3 days after intrastriatal tumor inoculation. In contrast, there was no activation or migration of endogenous subventricular zone (SVZ) neuroblasts in response to an intrastriatal syngeneic tumor. In conclusion, NPC possess the ability to influence tumor growth as well as respond to queues from the tumor or tumor microenvironment, demonstrating a cross-talk between the cells.     

人血管内皮抑素腺相关病毒载体包装质粒0pSNAV-hEndostatin-CMV-EGFP的构建

目的:构建人血管内皮抑素(Endostatin)腺相关病毒(Adeno-associated virus,AAV)载体包装质粒pSNAV-hEndostatin-CMV-EGFP.方法:采用分子克隆技术,从pCD-sEndostatin质粒获得hEndostatin cDNA,并将PCR扩增产物插入至AAV包装质粒pSNAV上,构建pSNAV-hEndostatin-CMV-EGFP的AAV重组质粒,经PCR、酶切及测序鉴定.结果:经PCR、酶切鉴定及基因测序证实AAV包装质粒pSNAV-hEndostatin-CMV-EGFP构建成功.结论:构建的AAV包装质粒pSNAV-hEndostatin-CMV-EGFP可作为rAAV-hEndostatin-EGFP表达载体的包装质粒.     

Chemical vectors for gene delivery: a current review on polymers, peptides and lipids containing histidine or imidazole as nucleic acids carriers

DNA/cationic lipid (lipoplexes), DNA/cationic polymer (polyplexes) and DNA/cationic polymer/cationic lipid (lipopolyplexes) electrostatic complexes are proposed as non-viral nucleic acids delivery systems. These DNA-nanoparticles are taken up by the cells through endocytosis processes, but the low capacity of DNA to escape from endosomes is regarded as the major limitations of their transfection efficiency. Here, we present a current report on a particular class of carriers including the polymers, peptides and lipids, which is based on the exploitation of the imidazole ring as an endosome destabilization device to favour the nucleic acids delivery in the cytosol. The imidazole ring of histidine is a weak base that has the ability to acquire a cationic charge when the pH of the environment drops bellow 6. As it has been demonstrated for poly(histidine), this phenomena can induce membrane fusion and/or membrane permeation in an acidic medium. Moreover, the accumulation of histidine residues inside acidic vesicles can induce a proton sponge effect, which increases their osmolarity and their swelling. The proof of concept has been shown with polylysine partially substituted with histidine residues that has caused a dramatic increase by 3–4.5 orders of magnitude of the transfection efficiency of DNA/polylysine polyplexes. Then, several histidine-rich polymers and peptides as well as lipids with imidazole, imidazolinium or imidazolium polar head have been reported to be efficient carriers to deliver nucleic acids including genes, mRNA or SiRNA in vitro and in vivo. More remarkable, histidylated carriers are often weakly cytotoxic, making them promising chemical vectors for nucleic acids delivery.This article is part of a themed section on Vector Design and Drug Delivery. For a list of all articles in this section see the end of this paper, or visit: http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2009