活菌疫苗载体的研究与应用

目前在疫苗研究中,要求新型疫苗不仅能够激发高效持久的免疫应答,而且应易于接种、生产费用低。减毒或无毒的活微生物作为疫苗载体能够激起持久的系统和黏膜免疫反应,批量制备成本较低,且具有良好的安全性,近年来已成为疫苗研究领域的热点。本文综述了几种活菌疫苗载体,包括沙门氏菌、卡介苗、耶尔森菌等的研究状况及其在疫苗载体方面的应用。     

Streptococcus pneumoniae proteomics: determinants of pathogenesis and vaccine development

Streptococcus pneumoniae is a major pathogen that is responsible for a variety of invasive diseases. The bacteria gain entry initially by establishing a carriage state in the nasopharynx from where they migrate to other sites in the body. The worldwide distribution of the bacteria and the severity of the diseases have led to a significant level of interest in the development of vaccines against the bacteria. Current vaccines, based on the bacterial polysaccharide, have a number of limitations including poor immunogenicity and limited effectiveness against all pneumococcal serotypes. There are many challenges in developing vaccines that will be effective against the diverse range of isolates and serotypes for this highly variable bacterial pathogen. This review considers how proteomic technologies have extended our understanding of the pathogenic mechanisms of nasopharyngeal colonization and disease development as well as the critical areas in developing protein-based vaccines.     

人和动物条件致病菌环境菌株侵染植物的研究进展北大核心CSCD

越来越多的研究表明某些在环境中普遍存在的人与动物的病原微生物能够跨界侵染不同生物界的寄主。本文就Serratia marcescens,Enterobacter cloacae,Pseudomonas aeuriginosa,Klebsiella pneumoniae等动物条件病原细菌环境菌株跨界侵染植物的研究现状进行了综述。这些病原菌在自然界中普遍存在,能够利用与感染人类相同或不同的侵染策略跨界侵染植物,以拓宽其寄主范围。其中,肺炎克雷伯氏菌(Klebsiella pneumoniae)能在自然条件下引起玉米发生顶腐病,揭示了环境中的某些植物可作为各种病原细菌的天然储存库,在条件合适的情况下可能会感染人类和动物,以及在食品生产中的潜在危害。对这些跨界病原菌的研究,在人、动物和植物流行病学上具有非常重要意义,也为环境科学提出了新的研究热点。     

Approaches To New Vaccines

ABSTRACT:?

The explosive technological advances in the fields of immunology and molecular biology in the last 5 years had an enormous impact on the identification of candidate vaccines against diseases, which until a few years ago seemed uncontrollable. Increased knowledge of the immune system has helped to define the mechanisms that underlie successful immunization and is now being exploited to develop improved versions of existing vaccines and new vaccines against emerging pathogens, tumors, or autoimmune diseases. An understanding of the mechanisms of action of novel adjuvants and the development of new vector and delivery systems will have a major impact on vaccine strategies. The use of DNA encoding antigens from pathogenic viruses, bacteria, and parasites as vaccines is a new approach that is receiving considerable attention. This and other innovative approaches, including vaccine production in plants, are appraised in this review. The successful eradication of smallpox and the imminent eradication of poliomyelitis by worldwide immunization campaigns provide positive examples of how the vaccine-mediated approach can lead to disease elimination; with the advent of new vaccines and improved delivery systems, there is no scientific reason why these successes cannot be repeated.     

Non-conventional therapeutic technique to replace CRISPR bacteria from biofilm by inducible lysogen

ABSTRACT

Bacteriophage can be an effective means of regulating bacterial populations when conditions allow phage invasion of bacterial colonies. Phage can either infect and lyse a host cell, or insert their DNA into the host cell genome; the latter process is called lysogeny. The clustered regularly interspaced short palindromic repeat (CRISPR) system, linked with CRISPR-associated (Cas) genes, is a regulatory system present in a variety of bacteria which confers immunity against bacteriophage. Studies of the group behaviour of bacteria with CRISPR/Cas systems have provided evidence that CRISPR in lysogenized bacteria can cause an inability to form biofilm. This allows CRISPR-immune bacteria in biofilms to effectively resist phage therapy. Our recent work has described a potential therapeutic technique to eradicate CRISPR-immune bacteria from a biofilm by a continuous influx of lysogens carrying an identical phage sequence. However, this model predicted that the CRISPR-immune population could persist for long times before eradication. Our current focus is on the use of diverse lysogens against CRISPR-capable bacterial populations. The goal of this work is to find a suitable strategy which can eradicate bacteria with a CRISPR system through the influx of finite amounts of distinct lysogens over fixed intervals.     

Viruses of hyperthermophilic Crenarchaea

Since the discovery of the Archaea--the third domain of life--by Woese and colleagues in 1977, the subsequent developments in molecular and cell biology, and also genomics, have strongly reinforced the view that archaea and eukarya co-evolved, separately from bacteria, over a long time. However, when one examines the archaeal viruses, the picture appears complex. Most viruses that are known to infect members of the kingdom Euryarchaeota resemble bacterial viruses, whereas those associated with the kingdom Crenarchaeota show little resemblance to either bacterial or eukaryal viruses. This review summarizes our current knowledge of this group of exceptional and highly diverse archaeal viruses.     

Plant‐based oral vaccines against zoonotic and non‐zoonotic diseases

The shared diseases between animals and humans are known as zoonotic diseases and spread infectious diseases among humans. Zoonotic diseases are not only a major burden to livestock industry but also threaten humans accounting for >60% cases of human illness. About 75% of emerging infectious diseases in humans have been reported to originate from zoonotic pathogens. Because antibiotics are frequently used to protect livestock from bacterial diseases, the development of antibiotic‐resistant strains of epidemic and zoonotic pathogens is now a major concern. Live attenuated and killed vaccines are the only option to control these infectious diseases and this approach has been used since 1890. However, major problems with this approach include high cost and injectable vaccines is impractical for >20 billion poultry animals or fish in aquaculture. Plants offer an attractive and affordable platform for vaccines against animal diseases because of their low cost, and they are free of attenuated pathogens and cold chain requirement. Therefore, several plant‐based vaccines against human and animals diseases have been developed recently that undergo clinical and regulatory approval. Plant‐based vaccines serve as ideal booster vaccines that could eliminate multiple boosters of attenuated bacteria or viruses, but requirement of injectable priming with adjuvant is a current limitation. So, new approaches like oral vaccines are needed to overcome this challenge. In this review, we discuss the progress made in plant‐based vaccines against zoonotic or other animal diseases and future challenges in advancing this field.     

基于CRISPR-Cas系统的基因组定点修饰新技术

CRISPR(clustered regulatory interspersed short palindromic repeat)序列源于原核生物的一种获得性免疫系统,协同Cas(CRISPR-associated)蛋白家族参与抵抗噬菌体或其它病毒的二次感染,广泛存在于细菌(60%)和古菌(90%)中.病菌和宿主的共同进化导致了CRISPR-Cas系统具有多样性,可分为3大类(Ⅰ-Ⅲ),又分为10亚类.在Ⅱ型CRISPR-Cas系统基础上建立了RNA介导的CRISPR-Cas系统来修饰(删除、添加、激活、抑制)靶细胞中特定的基因序列,现已在人类细胞、小鼠、斑马鱼、酵母、细菌、果蝇、线虫、拟南芥中得以应用.本文主要介绍了Ⅱ型CRISPR-Cas系统的结构特点、作用机理及作为新型基因组定点修饰技术的研究进展,分析该技术优势,并展望CRISPRCas系统的应用前景.     

Helper bacteria and pathogenicity assessments

In the field, pathogens exist in a diverse and dynamic ecological environment with other organisms (Blakeman, 1993; Preece & Dickinson, 1971). We tend to assume that these other organisms are 'benign' or perhaps in competition with the pathogen to occupy a particular niche. However, bacteria are often observed to be in close association with pathogens, as witnessed by the difficulty of eliminating them during isolation of pathogens involved in plant diseases. We now have clear evidence (Dewey et al ., pp. 489–497 in this issue) that they are sometimes neither benign, nor in competition, but actually helping the pathogen successfully infect its host even when the bacteria themselves are not pathogens of that host.     

腺病毒载体在疫苗研究中的应用

以病毒为载体的活疫苗为疾病预防和治疗研究提供了新手段。目前用于疫苗研究的病毒载体主要包括痘苗病毒载体、腺病毒载体、腺相关病毒载体、单纯疱疹病毒载体及逆转录病毒载体等。其中,重组腺病毒载体因其基因组大小适中,易于基因重组操作,繁殖滴度高,易于大量制备和保存,宿主范围广,转导效率高,安全性好,能刺激机体产生强烈的体液和细胞免疫反应等特点,而被广泛应用于重要感染性疾病及恶性肿瘤的疫苗研究。腺病毒载体在人免疫缺陷病毒(HIV)疫苗研究和临床试验中的成败更是备受关注。然而,与其他载体疫苗一样,机体对载体的免疫反应仍是阻碍腺病毒载体疫苗在临床中广泛应用的主要问题。那么,腺病毒载体解决这类问题的优势何在?我们简要综述腺病毒载体的特点及其在疫苗研究中的应用和存在的问题,为进一步优化和利用腺病毒载体在疫苗方面的研究提供参考。     

植物口服疫苗的研究进展

植物口服疫苗是通过转基因植物生产,通过口服的方式预防疾病的生物制品.作为一种新型疫苗,其研究开始于三十几年前.由于植物口服疫苗可以最大程度地降低传统疫苗的潜在风险,在疫苗生产中具有优势,因此拥有良好的商业生产前景.植物疫苗价格低廉,生产过程安全,可产生与注射疫苗相似效价效果,无论是在控制养殖业抗生素滥用的情况下作为替代...     

Applied aspects of Rhodococcus genetics

Eubacteria of the genus Rhodococcus are a diverse group of microorganisms commonly found in many environmental niches from soils to seawaters and as plant and animal pathogens. They exhibit a remarkable ability to degrade many organic compounds and their economic importance is becoming increasingly apparent. Although their genetic organisation is still far from understood, there have been many advances in recent years. Reviewed here is the current knowledge of rhodococci relating to gene transfer, recombination, plasmid replication and functions, cloning vectors and reporter genes, gene expression and its control, bacteriophages, insertion sequences and genomic rearrangements. Further fundamental studies of Rhodococcus genetics and the application of genetic techniques to the these bacteria will be needed for their continued biotechnological exploitation.     

小鼠对鼠伤寒沙门氏菌感染免疫应答的研究进展

小鼠鼠伤寒沙门氏菌感染后,会引发一系列的肠道和全身性的疾病,这是一种类似于人感染伤寒沙门氏菌的疾病。在感染的早期,天然免疫系统能迅速对入侵的细菌做出反应,吞噬细胞的活化以及炎症因子的产生能在一定程度上抑制鼠伤寒沙门氏菌的增殖,而在感染的后期,对于有效地控制和消灭细菌,获得性免疫是必要的。鼠伤寒沙门氏菌的感染能诱导特异性CD4+和CD8+T细胞的增殖,从而引发强烈的免疫应答,在此过程中也会产生大量的B细胞。特异性T细胞以及B细胞介导的免疫反应能有效地抵御细菌的侵染。总而言之在天然免疫系统和获得性免疫系统协调作用下,实现了对宿主的免疫保护。     

Going viral: next-generation sequencing applied to phage populations in the human gut

Over the past decade, researchers have begun to characterize viral diversity using metagenomic methods. These studies have shown that viruses, the majority of which infect bacteria, are probably the most genetically diverse components of the biosphere. Here, we briefly review the incipient rise of a phage biology renaissance, which has been catalysed by advances in next-generation sequencing. We explore how work characterizing phage diversity and lifestyles in the human gut is changing our view of ourselves as supra-organisms. Finally, we discuss how a renewed appreciation of phage dynamics may yield new applications for phage therapies designed to manipulate the structure and functions of our gut microbiomes.     

Efficacy comparison of adjuvants in PcrV vaccine against Pseudomonas aeruginosa pneumonia

Vaccination against the type III secretion system of P. aeruginosa is a potential prophylactic strategy for reducing the incidence and improving the poor prognosis of P. aeruginosa pneumonia. In this study, the efficacies of three different adjuvants, Freund's adjuvant (FA), aluminum hydroxide (alum) and CpG oligodeoxynucleotide (ODN), were examined from the viewpoint of inducing PcrV‐specific immunity against virulent P. aeruginosa. Mice that had been immunized intraperitoneally with recombinant PcrV formulated with one of the above adjuvants were challenged intratracheally with a lethal dose of P. aeruginosa. The PcrV–FA immunized group attained a survival rate of 91%, whereas the survival rates of the PcrV–alum and PcrV–CpG groups were 73% and 64%, respectively. In terms of hypothermia recovery after bacterial instillation, PcrV–alum was the most protective, followed by PcrV–FA and PcrV–CpG. The lung edema index was lower in the PcrV–CpG vaccination group than in the other groups. PcrV–alum immunization was associated with the greatest decrease in myeloperoxidase in infected lungs, and also decreased the number of lung bacteria to a similar number as in the PcrV–FA group. There was less neutrophil recruitment in the lungs of mice vaccinated with PcrV–alum or PcrV–CpG than in those of mice vaccinated with PcrV–FA or PcrV alone. Overall, in terms of mouse survival the PcrV–CpG vaccine, which could be a relatively safe next‐generation vaccine, showed a comparable effect to the PcrV–alum vaccine.     

Development of lipid-core-peptide (LCP) based vaccines for the prevention of group A streptococcal (GAS) infection

Traditional vaccines consisting of whole attenuated micro-organisms, or microbial components administered with adjuvant, have been demonstrated as one of the most cost-effective and successful public health interventions. Their use in large scale immunisation programs has lead to the eradication of smallpox, reduced morbidity and mortality from many once common diseases, and reduced strain on health services. However, problems associated with these vaccines including risk of infection, adverse effects, and the requirement for refrigerated transport and storage have led to the investigation of alternative vaccine technologies. Peptide vaccines, consisting of either whole proteins or individual peptide epitopes, have attracted much interest, as they may be synthesised to high purity and induce highly specific immune responses. However, problems including difficulties stimulating long lasting immunity, and population MHC diversity necessitating multiepitopic vaccines and/or HLA tissue typing of patients complicate their development. Furthermore, toxic adjuvants are necessary to render them immunogenic, and as such non-toxic human-compatible adjuvants need to be developed. Lipidation has been demonstrated as a human compatible adjuvant for peptide vaccines. The lipid-core-peptide (LCP) system, incorporating lipid adjuvant, carrier, and peptide epitopes, exhibits promise as a lipid-based peptide vaccine adjuvant. The studies reviewed herein investigate the use of the LCP system for developing vaccines to protect against group A streptococcal (GAS) infection. The studies demonstrate that LCP-based GAS vaccines are capable of inducing high-titres of antigen specific IgG antibodies. Furthermore, mice immunised with an LCP-based GAS vaccine were protected against challenge with 8830 strain GAS.     

Bacterial outer membrane vesicles: New insights and applications

Outer membrane vesicles (OMVs) (～50–250?nm in diameter) are produced by both pathogenic and nonpathogenic bacteria as a canonical end product of secretion. In this review, we focus on the OMVs produced by gram-negative bacteria. We provide an overview of the OMV structure, various factors regulating their production, and their role in modulating host immune response using a few representative examples. In light of the importance of the diverse cargoes carried by OMVs, we discuss the different modes of their entry into the host cell and advances in the high-throughput detection of these OMVs. A conspicuous application of OMVs lies in the field of vaccination; we discuss its success in immunization against human diseases such as pertussis, meningitis, shigellosis and aqua-farming endangering diseases like edwardsiellosis.     

Protective activity of the antilipopolysaccharide antibodies from human cord serum

We evaluated the ability of human maternal and cord serum antibodies to protect mice challenged with live Escherichia coli serotype O6:K2ac (E. coli O6). Mice received paired maternal or cord serum pools before a challenge with E. coli O6 to evaluate the mortality rate. All the pools were able to protect the animals challenged with bacteria except the test group from paired maternal and cord sera from preterm neonates containing less than 1.0 mg L(-1) immunoglobulin G antibody levels. In liver, spleen and mesenteric lymph nodes from the control group (phosphate-buffered saline), more than 10(2) CFU mL(-1) bacteria were found at 30 min and more than 10(5) CFU mL(-1) after 120 min. The test group showed lower bacterial counts in the organs, and no bacteria in the mesenteric lymph nodes during the evaluated period. Tumor necrosis factor alpha and interleukin 6 were undetectable in serum from animals pretreated with paired maternal and cord serum pools from full-term neonates and pools from preterm neonates containing high antibody and avidity levels. Our findings suggest that placental transfer of antilipopolysaccharide O6 immunoglobulin G antibodies to neonates has a high capacity to prevent lethal infection with E. coli O6 in a mouse protection model and that the degree of protection is determined by the concentration and avidity of these IgG antibodies.     

Symbiont recruitment versus ant-symbiont co-evolution in the attine ant-microbe symbiosis

The symbiosis between fungus-farming ants (Attini, Formicidae), their cultivated fungi, garden-infecting Escovopsis pathogens, and Pseudonocardia bacteria on the ant integument has been popularized as an example of ant-Escovopsis-Pseudonocardia co-evolution. Recent research could not verify earlier conclusions regarding antibiotic-secreting, integumental Pseudonocardia that co-evolve to specifically suppress Escovopsis disease in an ancient co-evolutionary arms-race. Rather than long-term association with a single, co-evolving Pseudonocardia strain, attine ants accumulate complex, dynamic biofilms on their integument and in their gardens. Emerging views are that the integumental biofilms protect the ants primarily against ant diseases, whereas garden biofilms protect primarily against garden diseases; attine ants selectively recruit ('screen in') microbes into their biofilms; and the biofilms of ants and gardens serve diverse functions beyond disease-suppression.