腹泻病控制计划1990年中期报告——疫苗部分

<正>1990年,与疫苗有关的研究主要是进行轮状病毒性腹泻和伤寒的候选疫苗的现场评价,同时支持研究开发新的和改进的针对轮状病毒性腹泻、志贺氏菌属性腹泻、霍乱及由肠毒性大肠杆菌引起的腹泻的候选疫苗。     

禽流感疫苗研究进展

禽流感是由正黏病毒科流感病毒属的A型流感病毒引起的 ,发生于各种家禽和野鸟的一种急性传染病。由于其重要的经济和公共卫生学意义 ,使得禽流感的防治显得突出重要。疫苗的使用是控制禽流感的主要手段。目前实际应用中仍以禽流感全病毒灭活疫苗为主 ,但由于其潜在的缺点使得人们将目光转向其它类型疫苗的研制。从常规疫苗、新型疫苗和交叉保护性疫苗三个方面对禽流感疫苗研究进展加以阐述。常规疫苗包括基因工程亚单位疫苗和重组活载体疫苗 :新型疫苗主要有冷适应流感弱毒疫苗 ,基因工程活流感病毒疫苗 ,复制缺陷型病毒疫苗 ,DNA疫苗 ,RNA复制子疫苗 ,表位疫苗等 :交叉保护性疫苗主要依据流感病毒表面的保守蛋白M和NP的特性 ,构建疫苗来达到交叉保护的目的。     

肺炎球菌疫苗进展

人们对肺炎球菌的认识始于19世纪80年代初期,1911年开始用肺炎球菌疫苗来预防肺炎球菌性疾病。迄今已发现90余个不同的肺炎球菌的功型,但仅有少数是引起疾病的。本文对肺炎球菌疫苗的研究进展作一简要综述,主要包括全菌体疫苗,荚膜多糖疫苗,以及荚膜多糖－蛋白结合疫苗的研究进展概况。     

疫苗研制技术的现状与展望

感染性病原是引起人类发病和死亡的主要原因之一。研制预防性疫苗和治疗性疫苗仍然是解决感染性疾病最有效和最有前景的方法,本文就疫苗研制领域的近来研究现状,包括疫苗研制技术的发展阶段,载体疫苗,粘膜免疫,新型佐剂和治疗性疫苗进行了综述,并对理想的新一代疫苗进行了简要的展望。     

基于融合蛋白的呼吸道合胞病毒疫苗的研究进展

呼吸道合胞病毒(respiratory syncytial virus,RSV)是一种引起严重下呼吸道感染的病原体,易感人群为婴幼儿、老年人及免疫功能低下者。目前尚无有效的抗病毒药物和预防疫苗。RSV融合蛋白(fusion protein,F蛋白)具有高度保守性,其诱导的抗体可同时抑制A型和B型两个亚型的RSV感染。因此,以F蛋白作为靶抗原的RSV亚单位疫苗、颗粒样疫苗和病毒载体疫苗是目前研究的主要策略。现就基于F蛋白的RSV疫苗研究进展作一综述。     

猪支原体肺炎基因工程疫苗的研究进展

猪支原体肺炎(Mycoplasmal pneumoniae of swine,MPS)是由猪肺炎支原体(Mycoplasma hyopneumonia,Mhp)引起的一种慢性呼吸道传染病,该病给养猪业造成了巨大的经济损失。疫苗接种是目前减轻或预防由猪肺炎支原体感染引发经济损失的主要手段。对猪支原体肺炎基因工程疫苗近年来的研究进展进行综述,主要包括黏附因子相关疫苗、核苷酸还原酶相关疫苗、DNA疫苗、表达文库疫苗和肽疫苗等,最后对基因工程疫苗研究工作的继续开展提供了建议。     

衣原体疫苗研究进展

衣原体是一类专一细胞内寄生的人兽共患病病原体,所引起的动物及人类疾病相当广泛。本文以亚单位疫苗及DNA疫苗为重点,对衣原体疫苗的研究状况做了简要的介绍。     

轮状病毒疫苗有效性及其影响因素的研究进展

A组轮状病毒(Rotavirus,RV)是引起5岁以下儿童腹泻的主要病原体之一。世界卫生组织建议将轮状病毒疫苗纳入计划免疫程序,但同一种疫苗在不同国家或地区的免疫反应和有效性表现不同。现就已上市的轮状病毒疫苗的有效性及影响因素予以综述,为新的轮状病毒疫苗研发、临床设计及免疫策略的制定提供参考。     

AIDS疫苗在灵长类动物模型中的发展

AIDS病是HIV感染引起的一种世界性的严重病毒病。发展一个安全、高效的疫苗将是最终控制HIV蔓延的方法。目前对AIDS疫苗的研究主要集中在全病毒灭活疫苗、病毒样颗粒疫苗、亚单位疫苗和多肽疫苗、减毒活疫苗、活载体疫苗和核酸疫苗等。在检验新型AIDS疫苗策略方面 ,非人灵长类动物模型能较好地反映HIV感染人体过程 ,有很重要的价值。现在主要有三种非人灵长类模型 :HIV 1感染的大猩猩、HIV 2感染的恒河猴 ;SIV感染的恒河猴及SHIV感染的恒河猴。本文就AIDS疫苗在灵长类动物模型中的最新发展作一综述。     

细菌性腹泻病疫苗的研究进展

细菌引起的肠道感染是对全世界人民健康的一大威胁。疫苗是预防腹泻病最经济、有效的手段。本文对细菌性腹泻病疫苗研究的现状进行了总结,包括困难、主要细菌疫苗的国内外进展和未来的研究方向。     

Challenges for development of hepatitis C virus vaccines

Abstract: Impediments to the development of a hepatitis C virus (HCV) vaccine are reviewed. Foremost is the perception that the limited transmissability of HCV, and reduced spread by blood-associated routes, make this a low priority target. It is argued that such a vaccine may have an important therapeutic use in the treatment of chronic HCV carriers of which an estimated 30 million exist worldwide. An HCV vaccine would also have prophylactic use in multivalent (hepatitis) vaccines, and in the developing world. An effective HCV vaccine vaccine will not be easy to develop. The high variability of the viral proteins, especially that of the envelope proteins, provide a major challenge. The association of HCV with very low density lipoproteins renders a major proportion of the virions non-neutralizable, a further challenge. It may be necessary to design an HCV vaccine which acts primarily through the generation of cytotoxic lymphocytes reactive with conserved epitopes displayed on the surface of infected cells.     

Persistent replication of a hepatitis C virus genotype 1b‐based chimeric clone carrying E1, E2 and p6 regions from GB virus B in a New World monkey

The development of effective hepatitis C virus (HCV) vaccines is essential for the prevention of further HCV dissemination, especially in developing countries. Therefore the aim of this study is to establish a feasible and immunocompetent surrogate animal model of HCV infection that will help in evaluation of the protective efficacy of newly developing HCV vaccine candidates. To circumvent the narrow host range of HCV, an HCV genotype 1b‐based chimeric clone carrying E1, E2 and p6 regions from GB virus B (GBV‐B), which is closely related to HCV, was generated. The chimera between HCV and GBV‐B, named HCV/G, replicated more efficiently as compared with the HCV clone in primary marmoset hepatocytes. Furthermore, it was found that the chimera persistently replicated in a tamarin for more than 2 years after intrahepatic inoculation of the chimeric RNA. Although relatively low (<200 copies/mL), the viral RNA loads in plasma were detectable intermittently during the observation period. Of note, the chimeric RNA was found in the pellet fraction obtained by ultracentrifugation of the plasma at 73 weeks, indicating production of the chimeric virus. Our results will help establish a novel non‐human primate model for HCV infection on the basis of the HCV/G chimera in the major framework of the HCV genome.     

丙型肝炎病毒多表位DNA疫苗的研究进展

丙型肝炎病毒（hepatitis C virus,HCV）是非甲非乙型肝炎的主要病原,目前还没有有效的预防和治疗手段。多表位DNA疫苗(multi-epitope DNA vaccine, minigenes/epigenes)是指通过筛选与组合优势抗原表位(包括T细胞、B细胞表位)基因,以能产生高效细胞、体液免疫应答进而清除HCV病毒为目的的新型核酸疫苗。其优势在于通过选择最具免疫保护潜力的表位以覆盖尽量多的病毒亚型和诱导全面的机体抗病毒免疫应答,并尽量减少无关、干扰和抑制序列可能产生的负面影响。本文介绍近年来国内外在丙型肝炎多表位DNA疫苗方面的研究进展,并展望了其发展方向。     

DNA immunization with a plasmid carrying the gene of hepatitis C virus protein 5A (NS5A) induces an effective cellular immune response

In spite of extensive research, no effective vaccine against hepatitis C virus (HCV) has been developed so far. DNA immunization is a potent technique of vaccine design strongly promoting the cellular arm of immune response. The genes encoding nonstructural HCV proteins (NS2-NS5B) are promising candidates for vaccine development. NS5A is a protein involved in viral pathogenesis, in the induction of immune response, and probably in viral resistance to interferon treatment. The objective of this study was to construct a DNA vaccine encoding NS5A protein and evaluate its immunogenicity. A plasmid encoding a full-size NS5A protein was produced using the pcDNA3.1 (+) vector for eukaryotic expression system. The expression of the NS5A gene was confirmed by immunoperoxidase staining of the transfected eukaryotic cells with anti- NS5A monoclonal antibodies. Triple immunization of mice with the plasmid vaccine induced a pronounced cellular immune response against a broad spectrum of NS5A epitopes as assessed by T-cell proliferation and secretion of antiviral cytokines IFN-γ and IL-2. In T-cell stimulation in vitro experiments, NS5A-derived antigens were modeled by synthetic peptides, recombinant proteins of various genotypes, and phages carrying exposed NS5A peptides. A novel immunomodulator Immunomax showed high adjuvant activity in DNA immunization. The data obtained indicate that the suggested DNA construct has a strong potential in the development of the gene vaccines against hepatitis C.     

Viral interference: A potential therapeutic method for chronic viral hepatitis?

Viral interference exists between different viral hepatitis. Acute Hepatitis C virus (HCV) super-infection on Hepatitis B virus (HBV) chronic carriers showed an inhibition of the HBV genome. And acute HBV super-infection on HCV chronic carriers indicated a similar interaction. In these cases, if the acute liver viral super-infection presents a self-limited course, the patients may be free from both viral infections or at least with undetectable underlying chronic viremia. The mechanism of viral interference is still undefined. Anyway this still leads to the hypothesis of using one hepatitis virus (live attenuated vaccine) to treat another hepatitis virus.     

A Protocol for Analyzing Hepatitis C Virus Replication

Hepatitis C Virus (HCV) affects 3% of the world’s population and causes serious liver ailments including chronic hepatitis, cirrhosis, and hepatocellular carcinoma. HCV is an enveloped RNA virus belonging to the family Flaviviridae. Current treatment is not fully effective and causes adverse side effects. There is no HCV vaccine available. Thus, continued effort is required for developing a vaccine and better therapy. An HCV cell culture system is critical for studying various stages of HCV growth including viral entry, genome replication, packaging, and egress. In the current procedure presented, we used a wild-type intragenotype 2a chimeric virus, FNX-HCV, and a recombinant FNX-Rluc virus carrying a Renilla luciferase reporter gene to study the virus replication. A human hepatoma cell line (Huh-7 based) was used for transfection of in vitro transcribed HCV genomic RNAs. Cell-free culture supernatants, protein lysates and total RNA were harvested at various time points post-transfection to assess HCV growth. HCV genome replication status was evaluated by quantitative RT-PCR and visualizing the presence of HCV double-stranded RNA. The HCV protein expression was verified by Western blot and immunofluorescence assays using antibodies specific for HCV NS3 and NS5A proteins. HCV RNA transfected cells released infectious particles into culture supernatant and the viral titer was measured. Luciferase assays were utilized to assess the replication level and infectivity of reporter HCV. In conclusion, we present various virological assays for characterizing different stages of the HCV replication cycle.     

Protective vaccination with hepatitis C virus NS3 but not core antigen in a novel mouse challenge model

BACKGROUND: Efficient vaccines against hepatitis C virus (HCV) infection are urgently needed. Vaccine development has been hampered by the lack of suitable small animal models to reliably test the protective capacity of immmunization. METHODS: We used recombinant murine gammaherpesvirus 68 (MHV-68) as a novel challenge virus in mice and tested the efficacy of heterologous candidate human vaccines based on modified vaccinia virus Ankara or adenovirus, both delivering HCV non-structural NS3 or core proteins. RESULTS: Recombinant MHV-68 expressing NS3 (MHV-68-NS3) or core (MHV-68-core) were constructed and characterized in vitro and in vivo. Mice immunized with NS3-specific vector vaccines and challenged with MHV-68-NS3 were infected but showed significantly reduced viral loads in the acute and latent phase of infection. NS3-specific CD8+ T cells were amplified in immunized mice after challenge with MHV-68-NS3. By contrast, we did neither detect a reduction of viral load nor an induction of core-specific CD8+ T cells after core-specific immunization. CONCLUSIONS: Our data suggest that the challenge system using recombinant MHV-68 is a highly suitable model to test the immunogenicity and protective capacity of HCV candidate vaccine antigens. Using this system, we demonstrated the usefulness of NS3-specific immunization. By contrast, our analysis rather discarded core as a vaccine antigen.     

Broadly neutralizing antibodies protect against hepatitis C virus quasispecies challenge

A major problem in hepatitis C virus (HCV) immunotherapy or vaccine design is the extreme variability of the virus. We identified human monoclonal antibodies (mAbs) that neutralize genetically diverse HCV isolates and protect against heterologous HCV quasispecies challenge in a human liver-chimeric mouse model. The results provide evidence that broadly neutralizing antibodies to HCV protect against heterologous viral infection and suggest that a prophylactic vaccine against HCV may be achievable.     

MicroRNA in HCV infection and liver cancer

In the more than two-decades since hepatitis C virus (HCV) was identified, there has been considerable improvement in our understanding of virus life cycle due largely to the development of in vitro culture systems for virus replication. Still challenges remain: HCV infection is a major risk factor for chronic hepatitis, liver cirrhosis and hepatocellular carcinoma worldwide; yet mechanistic details of HCV infection-associated hepatocarcinogenesis remain incompletely understood. A protective vaccine is not yet available, and current therapeutic options result in sustained virus clearance only in a subset of patients. Recent interest has focused on small non-protein coding RNAs, microRNAs (miRNAs), the dependence of virus replication on miRNAs, and miRNA-regulated genes in liver cancer. Functional analysis of the miRNA-targeted genes in liver cancer has advanced our understanding of the "oncomiRs" and their role in hepatocarcinogenesis. This review focuses on the dependence of HCV replication on miRNA and role of miRNA-targeted tumor suppressor genes as molecular markers of and possible targets for developing oncomiR-targeted therapy of chronic hepatitis and HCC. This article is part of a Special Issue entitled: MicroRNAs in viral gene regulation.     

丙型肝炎病毒保护性抗原及其疫苗研究的现状与展望

研制实用有效的HCV疫苗是控制HCV感染的一项根本措施。本文就近年来有关HCV保护性抗原及其疫苗的研究现状进行了综述,并就HCV疫苗研制的有关问题进行了讨论。