表位疫苗:疫苗研制新策略

人类通过接种疫苗已控制了许多重大感染性疾病并且消灭了天花 ,这是有史以来 ,人类征服疾病最为辉煌的成绩。传统疫苗是将病原体灭活或减毒而制成的 ,但存在生物危害性和遗传变异致使原疫苗效力丧失等问题。表位疫苗 (epitopevaccine)是用抗原表位制备的疫苗 ,包括合成肽疫苗 (syntheticpeptidevaccine)、重组表位疫苗 (recombinantepitope basedvaccine)及表位核酸疫苗 (epitopeDNAvaccine ,minigenes/epigenes) ,是目前研制感染性疾病和恶性肿瘤疫苗的方向。1　表位疫苗研制的理论基础表位 (epitope)是抗原分子中决定抗原特异性的特殊化…     

抗寄生虫多肽疫苗的研制策略

多肽疫苗是一种新型疫苗，因其含有能被机体淋巴细胞识别的抗原表位，故可模拟靶抗原，并诱导机体产生保护性免疫应答。本文从免疫学基础理论以及与研制疫苗相关的预测表位、化学合成短肽，表位方库、单克隆抗体等技术方面，探讨了肽疫苗作为寄生虫病防治综合措施之一的可行性。     

抗寄生虫多肽疫苗的研制策略

多肽疫苗是一种新型疫苗,因其含有能被机体淋巴细胞识别的抗原表位,故可模拟靶抗原,并诱导机体产生保护性免疫应答。本文从免疫学基础理论以及与研制疫苗相关的预测表位、化学合成短肽、表位文库、单克隆抗体等技术方面,探讨了肽疫苗作为寄生虫病防治综合措施之一的可行性。     

疟原虫红前期的肽亚单位疫苗

用射线致弱的子孢子实验性免疫动物和人可诱导抗疟疾感染免疫力 ,表明了研制有效疟疾疫苗的可行性。由于缺乏体外培养系统 ,大量应用射线致弱的子孢子做疫苗是不可行的。含有不同抗原表位的合成肽亚单位疫苗可作为替代品。目前 ,表达子孢子和 /或肝期T、B细胞表位的亚单位疫苗已用于实验动物 ,它们具有很强的免疫原性且能诱导抗体和CD4 + 、CD8+ T细胞介导的保护性免疫。     

一氧化氮与血吸虫感染的研究进展

一氧化氮(NO)作为机体产生的功能多样的小分子自由基气体,在感染性疾病中既可作为一种有效的细胞毒效应分子对病原体发挥杀灭作用,同时也是一种炎症反应因子。本文综述了NO在血吸虫感染过程中的作用及与疫苗保护性免疫的关系。     

一氧化氮与血吸虫感染的研究进展

一氧化氮（NO）作为机体产生的功能多样的小分子自由基气体，在感染性疾病中既可作为一种有效的细胞毒效应分子对病原体发挥杀灭作用，同时也是一种炎症反应因子。本综述了NO在血吸虫感染过程中的作用及与疫苗保护性免疫的关系。     

疟原虫红前期的肽亚单位疫苗

用射线致弱的子孢子实验性免疫动物和人可诱导抗疟疾感染免疫力，表明了研制有效疟疾疫苗的可行性。由于缺乏体外培养系统，大量应用射线致弱的子孢子做疫苗是不可行的。含有不同抗原表位的合成肽亚单位疫苗可作为替代品。目前，表达子孢子和/或肝期T、B细胞表位的亚单位疫苗已用于实验动物，它们具有很强的免疫原性且能诱导抗体和CD4^ T、CD8^ T细胞介导的保护性免疫。     

疟疾子孢子疫苗伍用Detox佐剂时的安全性、免疫原性和效果

抗疟原虫环子孢子(CS)蛋白重复区的多克隆和单克隆抗体被动转移给小鼠和猴,能抵抗子孢子诱导的疟疾。以伯氏疟原虫蛋白重复区为主要结构的合成肽和重组蛋白疫苗在实验动物亦显示诱导产生保护性免疫。为此,作者设计了恶性疟原虫的CS蛋白疫苗:含有B细胞表位的CS蛋白重复区(R32)T辅助细胞表位的流感病毒A非结     

弓形虫免疫作图蛋白1(TgIMP1)表位疫苗的设计及构建北大核心CSCD

目的设计基于弓形虫免疫作图蛋白1(TgIMP1)抗原蛋白的表位疫苗并进行结构验证。方法分别采用IEDB和ABCpred软件预测TgIMP1蛋白的B细胞抗原表位,分别采用SYFPEITHI和IEDB软件预测TgIMP1蛋白的T细胞抗原表位,运用DNA man比对筛选出T-B联合表位,在PfIMP2同源结构中验证表位性质并设计TgIMP1优势表位盒。结果通过计算机虚拟设计,得到了4条TgIMP1的优势B细胞表位(B1-B4)和2条优势T细胞表位(T1-T2),6条优势表位均处于PfIMP2结构外侧的无规卷曲区,且均为极性表面,适合作为表位疫苗的备选肽段。结论根据预测结果构建了3种TgIMP1优势表位盒,为多价表位疫苗的研发奠定基础。     

Q热疫苗研究

Q热(Q fever)为一种世界性分布的重要人兽共患病,疫苗接种是预防Q热的最有效手段。专性细胞内寄生的贝氏柯克斯体是Q热的病原体,灭活I相贝氏柯克斯体Q热疫苗(WCV)免疫保护效能几乎为100%,但是其免疫副反应强。氯仿-甲醇提取贝氏柯克斯体(CMR)和三氯醋酸提取贝氏柯克斯体可溶性抗原(TCA)Q热疫苗保留灭活Q热疫苗的免疫保护效能,且免疫副反应显著减轻。但CMR和TCA Q热疫苗均需要用鸡胚大量培养贝氏柯克斯体,需要在高等级生物防护实验室采用复杂步骤提取、纯化贝氏柯克斯体,这些使Q热疫苗的生产成本高、批量生产难。近十年来,国内外Q热疫苗研究着力于分子疫苗,并已经由研究贝氏柯克斯体保护性抗原转移到筛选能诱导特异性细胞免疫应答的CD4⁺和CD8⁺T细胞表位上,以期望T细胞表位在机体内高效表达,诱导机体产生良好的抗Q热保护性免疫应答。     

Preclinical development of an adjuvant-free peptide vaccine with activity against CMV pp65 in HLA transgenic mice

Epitope vaccines have shown promise for inducing cellular immune responses in animal models of infectious disease. In cases where cellular immunity was augmented, peptide vaccines composed of covalently linked minimal cytotoxic T-lymphocyte (CTL) and T-helper (T(H)) epitopes generally showed the most efficacy. To address a clinical vaccine strategy for cytomegalovirus (CMV) in the context of HCT (hematopoietic cell transplantation), we observed that linking the synthetically derived pan-DR epitope peptide (PADRE) or one of several tetanus T(H) epitopes to the immunodominant human leukocyte antigen (HLA) A*0201-restricted CTL epitope from CMV-pp65 to create a fusion peptide caused robust cytotoxic cellular immune responses in HLA A*0201/K(b) transgenic mice. Significantly, the fusion peptides are immunogenic when administered in saline solution by either subcutaneous or intranasal routes. CpG-containing single-stranded DNA (ss-oligodeoxynucleotide [ODN]) added to the fusion peptides dramatically up-regulated immune recognition by either route. Notably, target cells that either expressed full-length pp65 protein from vaccinia viruses or were sensitized with the CTL epitope encoded in the vaccine were recognized by splenic effectors from immunized animals. Visualization of murine peptide-specific CTL by flow cytometry was accomplished using an HLA A*0201 tetramer complexed with the pp65(495-503) CTL epitope. T(H)-CTL epitope fusion peptides in combination with CpG ss-ODN represent a new strategy for parenteral or mucosal delivery of vaccines in a safe and effective manner that has applicability for control or prophylaxis of infectious disease, especially in situations such as vaccination of donors or recipients of HCT, where highly inflammatory adjuvants are not desired.     

Oral vaccines

Oral vaccines are safe and easy to administer and convenient for all ages. They have been successfully developed to protect from many infectious diseases acquired through oral transmission. We recently found in animal models that formulation of oral vaccines in a nanoparticle-releasing microparticle delivery system is a viable approach for selectively inducing large intestinal protective immunity against infections at rectal and genital mucosae. These large-intestine targeted oral vaccines are a potential substitute for the intracolorectal immunization, which has been found to be effective against rectogenital infections but is not feasible for mass vaccination. Moreover, the newly developed delivery system can be modified to selectively target either the small or large intestine for immunization and accordingly revealed a regionalized immune system in the gut. Future applications and research endeavors suggested by the findings are discussed.     

衣原体mRNA疫苗的研发对策与展望北大核心CSCD

衣原体是一类专性胞内寄生、多宿主病原体,可感染眼部粘膜、呼吸道、泌尿生殖道等,引起人类与动物多种感染性疾病及并发症。然而衣原体常呈隐匿性感染,潜伏期长,临床上仅呈现轻微症状甚至无症状,抗生素治疗后常出现感染反复持续、迁延难愈现象,对人类公共卫生和畜牧业造成严重威胁。因此,研发安全高效的衣原体疫苗是防治衣原体感染的重要手段。mRNA疫苗是近年新兴的疫苗,在抗病毒、抗传染性疾病病原体方面应用广泛。过去几十年疫苗的研究显示,与全菌疫苗、亚单位疫苗以及DNA疫苗相比,mRNA疫苗不仅在安全性、免疫性、灵活性等方面更具优势,在传染病的预防方面也具有强大潜力。我们通过总结近年来衣原体疫苗以及mRNA疫苗的相关研究和重要发现,系统介绍合理研发衣原体mRNA疫苗过程中衣原体抗原选择、佐剂选择、抗原递送及免疫途径等重要环节及注意事项,为研发安全有效的衣原体mRNA理想疫苗提供设计思路和理论依据。     

The new generations of vaccines against parasites

The protection of humans and domestic animals against parasitic infections remains a major goal, especially in light of developing of drug resistant strains in many parasite species. "Classic" vaccines are based on attenuated infective stages of protozoan and helminth parasites. Although such vaccines are effective in confering host immunity against several protozoan (coccidiosis, giardiosis, toxoplasmosis) diseases and one helminth (dictyocaulosis) they are very unstable and expensive. Recombinant techniques enable to obtain protective antigens quickly and in considerable quantities, cultivating of the bacteria and purification of the recombinant protein is less expensive than the maintenance of host animals and isolation of the protective antigens from harvested parasites. Moreover, the cloned protective antigens may be deprived of epitopes responsible for immunopathology. However, at present only one anti-parasite recombinant protein vaccine is commercially available (TickGARD). Such a situation may result from that many protective parasitic antigens cannot be expressed in bacteria or yeast in anative from. DNA vaccines present many advantages over protein ones. Firstly, the antigenic proteins synthesised within the host cell possess an appropriate molecular structure and undergo a post-translational modifications specific for a native protein. The next advantage of DNA vaccines is that DNA is easier to handle and more resistant than proteins to temperature changes. DNA vaccines are likely to induce novel mechanisms of immune response, which may be beneficial in case of parasitic invasions. Costs of DNA vaccines are comparable, and may be even lower, in comparison to recombinant protein vaccines. The main obstacle preventing the use of DNA vaccines is still lack of the complete knowledge concerning mechanisms of their action. Vaccines based on transgenic plants (=edible vaccines), expressing the protective parasitic antigens, present another promising approach in research on anti-parasitic vaccines. Such vaccines may be of special importance in prevention of infections with gastrointestinal parasites.     

斑点热疫苗研究进展

斑点热是斑点热群立克次体引起的一类重要传染病,接种疫苗仍是预防斑点热的一种重要措施. 灭活立氏立克次体接种能够刺激实验动物产生特异性体液和细胞免疫,有效对抗该立克次体的致死性攻击,但对人体免疫的保护效果并不理想. 目前已发现的斑点热群立克次体的保护性抗原主要有外膜蛋白A、外膜蛋白B、YbgF和Adr2等表面蛋白,是研发斑点热分子疫苗的潜在候选分子. 单个保护性抗原免疫虽然能够诱导动物产生良好的特异性体液和细胞免疫应答,但是不能提供完全保护. 多个保护性抗原组合或保护性抗原的T和B淋巴细胞表位组合是研发斑点热分子疫苗的有效途径.     

Immunomodulatory vaccination in autoimmune disease.

The development of vaccines is arguably the most significant achievement in medicine to date. The practice of innoculation with the fluid from a sore to protect from a disease actually dates back to ancient China; however, with the introduction of Jenner's smallpox vaccine, and greater understanding of the immune system, vaccines have become specific and systematic. Traditional vaccines have used killed pathogens (hepatitis A and the Salk polio vaccines), immunogenic subunits of a given pathogen (hepatitis B subunit vaccine), or live attenuated pathogens (measles, mumps, rubella, Sabin polio vaccines) to generate protective immunity. Currently, a new generation of vaccines that use the genetic material of a pathogen to elicit protective immunity are being developed. Although the most widespread and successful use of vaccines today remains in the arena of infectious diseases, manipulations of immune responses to protect against cancers, neurologic diseases, and autoimmunity are being explored rigorously.     

Meta-analysis of immune epitope data for all Plasmodia: overview and applications for malarial immunobiology and vaccine-related issues

We present a comprehensive meta-analysis of more than 500 references, describing nearly 5000 unique B cell and T cell epitopes derived from the Plasmodium genus, and detailing thousands of immunological assays. This is the first inventory of epitope data related to malaria-specific immunology, plasmodial pathogenesis, and vaccine performance. The survey included host and pathogen species distribution of epitopes, the number of antibody vs. CD4⁺ and CD8⁺ T cell epitopes, the genomic distribution of recognized epitopes, variance among epitopes from different parasite strains, and the characterization of protective epitopes and of epitopes associated with parasite evasion of the host immune response. The results identify knowledge gaps and areas for further investigation. This information has relevance to issues, such as the identification of epitopes and antigens associated with protective immunity, the design and development of candidate malaria vaccines, and characterization of immune response to strain polymorphisms.     

Gene vaccines

Gene vaccines are a new approach to immunization and immunotherapy in which, rather than a live or inactivated organism (or a subunit thereof), one or more genes that encode proteins of the pathogen are delivered. The goal of this approach is to generate immunity against diseases for which traditional vaccines and treatments have not worked, to improve vaccines, and to treat chronic diseases. Gene vaccines make use of advances in immunology and molecular biology to more specifically tailor immune responses (cellular or humoral, or both) against selected antigens. They are still under development in research and clinical trials. The mechanisms for inducing cellular (as opposed to humoral) responses against a particular antigen have been elucidated. Gene vaccines provide a means to generate specific cellular responses while still generating antibodies, if desired. In addition, by delivering only the genes that encode the particular proteins against which a protective or therapeutic immune response is desired, the potential limitations and risks of certain other approaches can be avoided. This article describes the rationale for, immunologic mechanisms involved in, and design of gene vaccines under development. Preclinical and clinical studies of these vaccines are discussed for various clinical applications, focusing on infectious diseases.     

Peptide vaccination can lead to enhanced tumor growth through specific T-cell tolerance induction.

Vaccination with synthetic peptides representing cytotoxic T lymphocyte (CTL) epitopes can lead to a protective CTL-mediated immunity against tumors or viruses. We now report that vaccination with a CTL epitope derived from the human adenovirus type 5 E1A-region (Ad5E1A234-243), which can serve as a target for tumor-eradicating CTL, enhances rather than inhibits the growth of Ad5E1A-expressing tumors. This adverse effect of peptide vaccination was rapidly evoked, required low doses of peptide (10 micrograms), and was achieved by a mode of peptide delivery that induces protective T-cell-mediated immunity in other models. Ad5E1A-specific CTL activity could no longer be isolated from mice after injection of Ad5E1A-peptide, indicating that tolerization of Ad5E1A-specific CTL activity causes the enhanced tumor outgrowth. In contrast to peptide vaccination, immunization with adenovirus, expressing Ad5E1A, induced Ad5E1A-specific immunity and prevented the outgrowth of Ad5E1A-expressing tumors. These results show that immunization with synthetic peptides can lead to the elimination of anti-tumor CTL responses. These findings are important for the design of safe peptide-based vaccines against tumors, allogeneic organ transplants, and T-cell-mediated autoimmune diseases.     

Stimulation of protective CD8+ T lymphocytes by vaccination with nonliving bacteria.

Infectious diseases caused by intracellular microbes are responsible for major health problems, and satisfactory control will ultimately depend on efficient vaccination strategies. The general assumption is that activation of protective immune responses against intracellular microbes dominated by CD8+ T cells are achieved only by live vaccines. In contrast, we here demonstrate stimulation of protective immunity in mice against the intracellular pathogen Listeria monocytogenes by vaccination with heat-killed listeriae. Vaccine-induced immunity comprised cytolytic and interferon gamma-producing CD8+ T lymphocytes. CD8+ T cells from vaccinated donor mice transferred protection against listeriosis. Moreover, vaccination with heat-killed listeriae induced production in CD4+ T-cell-deficient, H2-A beta gene-disrupted mutant mice. We conclude that antigens from killed listeriae are introduced into the major histocompatibility complex class I pathway and thus are recognized by CD8+ T cells. The practicability of killed vaccines against human infectious diseases therefore should be reevaluated.