RNA复制子疫苗研究进展

最近兴起的RNA复制子疫苗,利用源自病毒的能够自主复制的RNA,其结构蛋白基因由外源抗原基因取代,保留了非结构蛋白(RNA复制酶)基因。RNA复制酶可使RNA载体在细胞质中高水平复制,并实现外源抗原基因的高水平表达,可同时诱导细胞免疫和体液免疫应答。大量双链RNA可诱导被感染细胞凋亡,宿主细胞的凋亡有利于免疫系统识别外源抗原。RNA复制子疫苗克服了传统疫苗和普通DNA疫苗存在的缺点,具有抗原表达效率高、安全性好、应用范围广等优点,因而被视为一种发展前景很好的疫苗形式。目前已对一些疾病模型基于复制子的治疗性和预防性疫苗进行了研究(涉及的对象包括病毒、肿瘤以及细菌毒素等),并对某些不足之处进行了改进。     

新型兽用疫苗的研究进展

新型兽用疫苗是免疫学和病毒学的研究热点,主要包括亚单位疫苗、基因工程缺失苗、重组病毒活载体疫苗和基因疫苗。上前已经被广泛的应用于研究和疫病的防治上。最近的疫苗发展方向集中于在基因疫苗上。高效、安全、稳定、成本低是疫苗开发的重点。本文介绍了新型疫苗的现状,以及今后发展的趋势和策略。     

基因工程技术在免疫学中的应用

基因工程技术已越来越广泛渗透到包括免疫学在内的生命科学的各个领域,无论在应用基础还是在开发研究方面都取得了惊人的进展,大量的基因工程疫苗、基因工程抗体、基因工程细胞因子和基因工程化细胞治疗技术等,已成功地应用于临床。１基因工程疫苗疫苗是免疫防治的重要...     

体外转录的自我复制型mRNA疫苗研究进展*

自我复制型mRNA是一种灵活的疫苗平台,该平台的开发基于甲病毒表达载体,其中复制必需基因得以完整保留,而结构蛋白基因则被来自病原的抗原基因替换。由于避免了病原培养、毒力返强和现存免疫的干扰,使其成为疫苗快速设计的理想平台。大量研究数据显示,此类疫苗可应用在人、小鼠、兔、猪、禽甚至鱼类体内诱导体液免疫和细胞免疫。过去,自我复制mRNA疫苗的研究采用重组单载体的模式,基因组骨架来源于辛德毕斯病毒、塞姆利基森林病毒和委内瑞拉马脑炎病毒。现在,反式复制型RNA和核酸修饰的反式复制型RNA作为下一代技术平台被寄予厚望。对基于甲病毒表达载体的mRNA疫苗技术的研究进展进行概述,重点介绍针对以流感病毒、新型冠状病毒和寨卡病毒等为代表的自我复制型mRNA疫苗研究现状,并探讨了该技术平台的未来发展方向。     

体外转录的自我复制型mRNA疫苗研究进展*

自我复制型mRNA是一种灵活的疫苗平台,该平台的开发基于甲病毒表达载体,其中复制必需基因得以完整保留,而结构蛋白基因则被来自病原的抗原基因替换。由于避免了病原培养、毒力返强和现存免疫的干扰,使其成为疫苗快速设计的理想平台。大量研究数据显示,此类疫苗可应用在人、小鼠、兔、猪、禽甚至鱼类体内诱导体液免疫和细胞免疫。过去,自我复制mRNA疫苗的研究采用重组单载体的模式,基因组骨架来源于辛德毕斯病毒、塞姆利基森林病毒和委内瑞拉马脑炎病毒。现在,反式复制型RNA和核酸修饰的反式复制型RNA作为下一代技术平台被寄予厚望。对基于甲病毒表达载体的mRNA疫苗技术的研究进展进行概述,重点介绍针对以流感病毒、新型冠状病毒和寨卡病毒等为代表的自我复制型mRNA疫苗研究现状,并探讨了该技术平台的未来发展方向。     

基因疫苗及增强其免疫效应的策略

基因疫苗被视为“第三次疫苗革命”,是目前疫苗研究领域的热点,本回顾了基因疫苗的诞生,阐述了其优越性,重点讨论了增强其免疫效应的策略,包括合理的载体设计,细胞因子及共刺激分子与抗原的共表达及适宜的接种途径等。     

人乳头瘤病毒16型E5与IL-12联合基因疫苗的免疫活性

为了研制人乳头瘤病毒16型(HPV16)防治性疫苗,分析了HPV16 E5与IL-12联合基因疫苗的免疫活性。将构建的pcDNA3.1(+)/E5与pcDNA3.1(+)/IL-12联合免疫BALB/c小鼠,以ELISA测定小鼠血清中抗HPV16 E5 IgG水平、小鼠脾细胞培养上清中IFN-γ和IL-4含量;MTT法检测脾淋巴细胞增殖反应。结果显示末次免疫后,联合基因疫苗组和单基因疫苗组血清IgG A450值分别明显高于pcDNA3.1(+)组、pcDNA3.1(+)/IL-12组和PBS组(P<0.01);且联合基因疫苗组显著高于单基因疫苗组(P<0.01)。联合基因疫苗组和单基因疫苗组的IFN-γ和IL-4含量分别均明显高于pcDNA3.1(+)组、pcDNA3.1(+)/IL-12组和PBS组IFN-γ和IL-4含量(P<0.01),且联合基因疫苗组含量显著高于单基因疫苗组(P<0.01)。联合基因疫苗组和单基因疫苗组脾淋巴细胞刺激指数(SI)分别显著高于pcDNA3.1(+)组、pcDNA3.1(+)/IL-12组和PBS组(P<0.01);联合基因疫苗组与单基因疫苗组比较,SI差异无统计学意义(P>0.05)。结果表明HPV16 E5单基因疫苗以及与IL-12联合基因疫苗均能刺激机体产生较强的免疫应答,且联合基因疫苗优于单基因疫苗。     

肿瘤基因疫苗的研究进展

基因疫苗技术自从20世纪90年代问世以来被迅速应用到传染病、免疫缺陷、肿瘤等重大疾病的预防和治疗的研究中,有一部分已经进入临床试验阶段.肿瘤基因疫苗可以打破免疫耐受,增强免疫原性,诱导机体产生针对肿瘤的体液和细胞反应,既有预防又有治疗肿瘤的作用.能够防治肿瘤的基因疫苗发展迅猛,主要包括与肿瘤相关抗原（TAAs）有关的全长、表位、独特型（Id）和融合DNA疫苗,能够自主复制的RNA疫苗,与树突细胞（DCs）相关的肿瘤基因疫苗等.肿瘤基因疫苗的分子作用机制及其存在的弊端也日益成为关注的问题.     

RNA复制子疫苗及其包装系统

RNA复制子疫苗是一种基于RNA的复制子,能够进行自我复制的新型疫苗,保留了病毒的复制酶基因,结构基因由外源基因所代替,复制酶可控制载体RNA在胞质中高水平复制和外源基因高水平的表达。RNA复制子疫苗被包装成病毒样颗粒后,大大提高了RNA复制子的稳定性。近几年来,关于RNA复制子的包装系统发展迅速,并且许多包装系统都获得成功,大大提高了复制子疫苗的生物安全性和外源基因的高效表达性,具有很好的应用前景。     

转基因植物疫苗免疫原基因表达研究概述

近年来 ,随着基因工程、蛋白质工程以及免疫学理论与技术的迅速发展 ,以开发新型高效疫苗为目标的新的研究领域异常活跃 ,基因工程亚单位疫苗、基因缺失疫苗、重组病毒活载体疫苗、核酸疫苗各展风姿 ,但这些系统存在设备复杂 ,成本高 ,免疫原性较差和外源微生物污染的缺陷 .为克服上述缺陷 ,进入 2 0世纪 90年代 ,以植物为生物反应器的疫苗研究策略迅速发展 ,短短几年以植物为生物反应器的可食性疫苗取得了可喜的进展 ,这些进展也开辟了植物生物技术革命的新天地 .1　转基因植物基因疫苗研究原理和策略利用转基因植物生产疫苗 ,是将抗原基因…     

Dendritic cell delivery of plasmid DNA

Positive human clinical data using biolistic-mediated gene transfer (i.e., gene gun) to administer a nucleic acid-based Hepatitis B vaccine has validated genetic immunization as an effective clinical vaccine modality. Although the precise mechanism of action has yet to be determined, preclinical studies using jet injection have indicated that direct targeting of resident antigen presenting cells (Langerhan's cells) in the skin as the primary immunological driving force for the potent and long-lived immune response. Moreover, positive results with topical delivery of genetic vaccines and ex vivo loading of dendritic cells with antigen has strengthened the movement toward directly targeting antigen presenting cells as a means to amplify, control, and mediate the immunological consequences of prophylactic and/or therapeutic genetic vaccines. Despite these encouraging results with the gene gun, it is unclear whether this technology will translate into commercially available vaccines due to potential product development barriers such as cost and convenience. It is clear that safety concerns in using genetic approaches to treat and prevent disease have highlighted the need for strict product requirements for genetic vaccines. A plausible strategy to meet these requirements is to combine controlled plasmid delivery systems with tissue-specific gene expression systems.     

基因疫苗导入技术研究进展

基因疫苗积极的临床结果证明了,基因免疫是一种有效的临床免疫模式。虽然,喷射注射法的精确作用机制还不太清楚,但临床前研究表明,在皮肤内直接打靶抗原呈递细胞可有效地增强免疫反应。另外,局部给药法和树突细胞体外加载抗原的实验结果显示,直接打靶抗原呈递细胞可放大、控制和调节预防及治疗性基因疫苗的免疫结果。尽管基因枪有许多令人鼓舞的优点,但由于价格和便利性的障碍,它是否能商业化还不能确定。利用基因法治疗和预防疾病所涉及的安全性对基因疫苗要求更严格。这要有可控的质粒导入系统和组织特异性表达系统。     

Two decades of plant-based candidate vaccines: a review of the chimeric protein approaches

Genetic engineering revolutionized the concept of traditional vaccines since subunit vaccines became reality. Additionally, over the past two decades plant-derived antigens have been studied as potential vaccines with several advantages, including low cost and convenient administration. More specifically, genetic fusions allowed the expression of fusion proteins carrying two or more components with the aim to elicit immune responses against different targets, including antigens from distinct pathogens or strains. This review aims to provide an update in the field of the production of plant-based vaccine, focusing on those approaches based on the production of chimeric proteins comprising antigens from human pathogens, emphasizing the case of cholera toxin/E. coli enterotoxin fusions, chimeric viruses like particles approaches as well as the possible use of adjuvant-producing plants as expression hosts. Challenges for the near future in this field are also discussed.     

Specific prophylaxis of shigellosis

A high level of shigellosis morbidity requires new approaches to the control of bacterial dysentery. According to modern concepts, the outbreaks of Shigella infections are linked both with less intensive epidemic control measures and the objective cyclic character of the epidemic process. In this connection great importance is attached to the development of vaccines for the immunization of high risk groups in territories with unfavorable epidemic conditions and in zones of military conflicts, as well as children of school and pre-school age, who mostly determine seasonal rises of shigellosis morbidity. In this article the data describing new approaches to the creation of new live enteric vaccines on the basis of the knowledge of the genetic control of microbial pathogenicity and the regulation of its expression are presented. Attenuated Shigella mutants, created by different authors and having good prospects to be used for the development of vaccines, are characterized.     

Progress in the development of pandemic influenza vaccines and their production technologies

This article analyzes the current situation in the field of construction and production of pandemic influenza vaccines. The main task of protecting the population against influenza pandemics requires state-of-the-art approaches to the construction of influenza vaccines to be based on reassortment and genetic engineering techniques, including the analysis of primary structures of influenza viral genes, synthesis and cloning of the main viral genes, reverse genetics techniques, and banks of plasmids bearing basic viral genes. Reassortant technologies are now giving way to new approaches for objective reasons. The state-of-the-art technologies provide safety not only at the laboratories where vaccine viruses are constructed but also make the production process wholly safe. We are using the following approaches to the development of industrial production: use of nanoparticles and nanoemulsions as functional adjuvants, construction of totally-safe strains for live attenuated influenza vaccines with deletions of molecular determinants of pathogenicity, application of protein and chemical chaperones to provide self-assembly of haemagglutinin molecules of the H1N1v-2009 virus, and impregnation of whole-virion preparations with nanoparticles to enhance antigenicity.     

Strategies for the plant-based expression of dengue subunit vaccines

Despite significant efforts in many countries, there is still no commercially viable dengue vaccine. Currently, attention is focused on the development of either live attenuated vaccines or live attenuated chimaeric vaccines using a variety of backbones. Alternate vaccine approaches, such as whole inactivated virus and subunit vaccines are in the early stages of development, and are each associated with different problems. Subunit vaccines offer the advantage of providing a uniform antigen of well-defined nature, without the added risk of introducing any genetic material into the person being inoculated. Preliminary trials of subunit vaccines (using dengue E protein) in rhesus monkeys have shown promising results. However, the primary disadvantages of dengue subunit vaccines are the low levels of expression of dengue proteins in mammalian or insect cells, as well as the added unknown risks of antigens produced from mammalian cells containing other potential sources of contamination. In the past two decades, plants have emerged as an alternative platform for expression of biopharmaceutical products, including antigens of bacterial, fungal or viral origin. In the present minireview, we highlight the current plant expression technologies used for expression of biopharmaceutical products, with an emphasis on plants as a production system for dengue subunit vaccines.     

Plasmid-only rescue of influenza A virus vaccine candidates.

The potential threat of another influenza virus pandemic stimulates discussion on how to prepare for such an event. The most reasonable prophylactic approach appears to be the use of effective vaccines. Since influenza and other negative-stranded RNA viruses are amenable to genetic manipulation using transfection by plasmids, it is possible to outline new reverse genetics-based approaches for vaccination against influenza viruses. We suggest three approaches. First, we use a plasmid-only rescue system that allows the rapid generation of high-yield recombinant vaccine strains. Second, we propose developing second-generation live influenza virus vaccines by constructing an attenuated master strain with deletions in the NS1 protein, which acts as an interferon antagonist. Third, we suggest the use of Newcastle disease virus recombinants expressing influenza virus haemagglutinin proteins of pandemic (epizootic) strains as novel vaccine vectors for use in animals and possibly humans.     

DNA vaccines: designing strategies against parasitic infections

The complexity of parasitic infections requires novel approaches to vaccine design. The versatility of DNA vaccination provides new perspectives. This review discusses the use of prime-boost immunizations, genetic adjuvants, multivalent vaccines and codon optimization for optimal DNA vaccine design against parasites.     

Traditional and novel approaches to flavivirus vaccines

Yellow fever, dengue, Japanese encephalitis and tick-borne encephalitis viruses are the medically most important members of the Flavivirus genus composed primarily of arboviruses. In this paper, we review the commercially available traditional flavivirus vaccines against yellow fever, Japanese encephalitis, and tick-borne encephalitis, as well as modern approaches to flavivirus vaccines. Formalin inactivation technology has been employed to produce killed vaccines. Flaviviruses have been attenuated by multiple passages in animal tissues and cell cultures to produce empirical live attenuated vaccines. The use of traditional methods is being pursued to develop vaccines against other flavivirus diseases, such as dengue, and to improve existing vaccines, such as for Japanese encephalitis. With the recent development of infectious clones, rational approaches to attenuated flavivirus vaccines have employed the introduction of specific mutations into wild type viruses and chimerisation between different viruses. Novel methods for delivery of live vaccines, such as inoculation of infectious DNA or RNA, have been described. Other approaches, such as the construction of protein subunit, expression vector-based and naked DNA vaccines, have been proposed to create alternate vaccine candidates.