溶菌酶——先天性免疫系统中的重要防御物质

先天性免疫系统被认为是机体的第一道防线,能抵抗多数病原菌。溶菌酶在生物体内普遍存在,其水平或活性是先天性免疫力的一个重要指标。溶菌酶存在于黏液、淋巴组织、血浆等体液中,也在多种组织中表达,可溶解革兰氏阳性菌和阴性菌细胞,本质上具有调理作用,能激活补体系统和吞噬细胞。随性别、年龄、季节、环境及疾病感染、压力程度的不同,溶菌酶活性也不同。本文综述了溶菌酶在先天性免疫系统中的作用。     

具有替代抗生素潜能的绿色生物制剂——溶菌酶

溶菌酶是能溶解细菌细胞壁的一类酶。是一类物质的的总称，是动物机体重要的免疫因子。广泛存在于机体各个部位。当外界有害菌入侵机体时，动物机体存在的溶菌酶可以分解细菌细胞壁中的粘多糖成分，使细菌内容物溢出，从而达到溶解细菌的目的。溶菌酶于1922年由发现青霉素的弗莱明首次发现。     

驴乳中的溶菌酶及其协同保健作用

溶菌酶可以降解细菌的细胞壁,具有杀菌、抗病毒、抗肿瘤等作用。每100g疆岳驴乳中含225mg溶菌酶,是人乳的20倍,牛乳的750倍以上。驴乳的抗菌消炎、提高机体免疫力、食疗康复等保健功效与溶菌酶浓度较高以及溶菌酶和其他免疫因子及营养物质的协同作用有密切关系。     

仔猪血清中溶菌酶含量和活力的测定

溶菌酶参与机体内多种免疫反应,测定它在血清中的含量可作为了解机体免疫功能的一个重要指标.试验用36头22日龄仔猪血清为试验样本,利用比浊法和ELISA两种方法测定血清中的溶菌酶.结果表明:ELISA测定法对同一样本3次测定值间的变异系数和对36个仔猪血清样本溶菌酶测定值变异系数均极显著(P＜0.01)小于比浊法测定结果...     

抗生素对蛋白中的溶菌酶有不良影响

自从知道溶菌酶具有可临床应用于治疗溃疡和传染病以及可用作某些抗生素的增效剂等潜在价值后,食品工业和化学工业就对于从蛋白中分离溶菌酶很感兴趣。已知蛋白中的溶菌酶含量为3.5％,因此它是溶菌酶最丰富的来源之一。溶菌酶是最早以结晶态获得的蛋白质之一,而且其化学结构也已完全明了。溶菌酶存在于多种多样的生物组织和液体中,表明其对生物机体有着极为重要的作用。     

互叶百千层提取物对仔猪血清溶菌酶的影响

溶菌酶是动物机体非特异性免疫的重要指标。通过测定仔猪血清中溶菌酶的含量变化来评价互叶百千层提取物对仔猪非特异性免疫力的影响。以灌服方式给仔猪饲喂不同浓度的提取物,以黄芪多糖、长效土霉素、以及不添加药物的空白组作为试验对照;观察测定仔猪腹泻发病率、死亡率,检测血清中溶菌酶含量。结果显示,该提取物能够显著提高仔猪血清中溶菌酶的含量,效果可与黄芪多糖媲美。该试验结果对提高植物提取物在防治仔猪腹泻中的开发与运用具有重要的意义。     

枸杞多糖对鲫鱼血清溶菌酶活性的影响

枸杞(LyciumbarbarumL.)具有增强机体免疫、抗氧化、抗疲劳等功能(王宁元等,2002;齐春会等,2001;罗琼等,1999)。枸杞多糖(LBP)是枸杞子中主要免疫活性成分,可以促进或改善动物机体的免疫功能(齐春会等,2001;罗琼等,1999)。溶菌酶是鱼类非特异性免疫系统的重要组成部分,是一种水解酶,主要作用于细菌细胞壁粘多糖的β-1,4糖苷键,同时对真菌、寄生虫以及病毒也有破坏作用。因此,溶菌酶在鱼类抵抗传染性疾病时起着重要作用。迄今为止,枸杞多糖免疫增强作用的研究主要以小鼠为试验对象,对鱼类免疫功能的影响目前未见报道。因此,本试验选取枸杞…     

保护机体的非特异性体液因素

机体对感染的自然抵抗力包括特异的和非特异的保护因素,它是通过细胞和体液免疫系统的共同作用来实现的。在血液和淋巴中实现机体自然抵抗力的重要体液因素包括备解素、补体、溶菌酶和杀菌活性等。这些因素对免疫感染起着早期屏障作用,给机体形成特异性免疫提供了时间。对血清中这些因素的深入研究为数不多,而且有些结果是相矛盾的,对淋巴中有关这     

溶菌酶替代抗生素的研究进展

溶菌酶是一种天然蛋白酶,它广泛存在于机体分泌物中,如眼泪、唾液和乳汁中。溶菌酶具有抗菌作用,它通过裂解肽聚糖中的糖苷键,以此使细菌细胞壁破裂,最终导致细胞死亡。本文就溶菌酶添加在饲料中可替代抗生素,作了简要综述。     

溶菌酶的应用研究进展

溶菌酶是人和动物体液和组织中的一种重要的防御因子，具有杀菌效果强，杀菌谱广，稳定性强，易被机体所接受的特点，还能促进免疫功能恢复，并且没有任何毒副作用和不良反应。因此溶菌酶作为一种生物制剂，被广泛应用于食品、饲料工业和医学临床。     

Toll样或非Toll样配体佐剂研究进展

有效的疫苗含有可活化天然免疫系统的佐剂组分,从而激发抗原特异性的免疫应答.Toll样受体(toll-like receptors,TLR)是一种重要的天然识别受体,大多数疫苗佐剂都是TLR配体.少数佐剂通过其他的识别受体和信号通路,以TLR非依赖性的方式来活化天然免疫系统.非Toll样配体佐剂的作用靶点主要是近来发现的NOD样受体(Nod-like receptor,NLR)、RIG(retinoic-acid-inducible gene)样受体(RIG-like receptors,RLR)等胞内天然免疫受体.文章对Toll样或非Toll样配体作为疫苗佐剂的研究进行了综述.     

Overview of the Immune Dynamics of the Digestive System

The digestive tract of the chicken is a major site of pathogen exposure. Although the bird has a multifaceted set of tools to prevent or resist infection, any activation of the immune system can divert nutrients away from production. Therefore, prevention of pathogenic exposure is preferred. However, it is unlikely that the bird can escape exposure to all pathogens during its life, thus the ability to respond to immunologic challenges is essential. The immune system of birds is similar to that of mammals in terms of structure and function, although some differences do exist, particularly in regulatory aspects. The innate immune system responds nonspecifically to foreign molecules and is essential for the induction of the specific (acquired) immune response. Cells of the innate immune system include macrophages, dendritic cells, heterophils, and natural killer cells. The acquired immune response involves recognition of a specific antigen and response by lymphocytes. Cytotoxic T lymphocytes are especially effective at inducing cells infected with intracellular pathogens to undergo apoptosis. Helper T lymphocytes increase the effectiveness of innate immune cells in combating extracellular pathogens and are also essential for activating B lymphocytes, which produce antibodies specific to the invading pathogen. All aspects of the immune system function together, although one aspect will often dominate, depending on the type and severity of the infection. This paper reviews the basics of avian immune function in general and discusses the immune system in the digestive tract in particular in birds. The consequences of activation of the immune system are presented.Currently, growth-promoting antibiotics are not used in poultry in many countries; the North American industry may be moving in that direction as well, either through legislation or consumer pressure. Several nonantibiotic means of manipulating the immune system to prevent the health- and performance-suppressing effects of immune system activation are presented here.     

视黄酸诱导基因-Ⅰ在家禽天然免疫应答中作用的研究进展

家禽的天然免疫应答在抵抗病毒感染的过程中起着关键性作用，视黄酸诱导基因-Ⅰ（retinoic acid inducible gene-Ⅰ，RIG-Ⅰ）作为细胞质内一类识别病毒双链RNA的模式识别受体，与天然免疫应答密切相关。它可通过RNA配体结合病原相关分子模式监测细胞质中的病毒RNA，此过程激活了RIG-Ⅰ及下游线粒体抗病毒信号蛋白（MAVS），最终导致干扰素调节因子（IRF3/7）和核因子κB （NF-κB）活化，诱导产生Ⅰ型干扰素等免疫细胞因子，进而使细胞做出相应的抗病毒天然免疫反应。但由于鸡体内缺乏RIG-Ⅰ基因，目前大多将鸭源或鹅源RIG-Ⅰ基因转染鸡成纤维母细胞（DF-1）研究RIG-Ⅰ基因在鸡感染禽类病毒时是否具有免疫功能。文章介绍了RIG-Ⅰ在家禽体内的表达及其介导的抗病毒天然免疫信号通路，并简述了RIG-Ⅰ在家禽体内抗病毒作用的研究概况，为抑制家禽病毒的感染和免疫系统研究，以及研制新型抗病毒疫苗或免疫佐剂等提供参考。     

Viral deubiquitinases and innate antiviral immune response in livestock and poultry

Among many of the pathogens, virus is the main cause of diseases in livestock and poultry. A host infected with the virus triggers a series of innate and adaptive immunity. The realization of innate immune responses involves the participation of a series of protein molecules in host cells, including receptors, signal molecules and antiviral molecules. Post-translational modification of cellular proteins by ubiquitin regulates numerous cellular processes, including innate immune responses. Ubiquitin-mediated control over these processes can be reversed by cellular or viral deubiquitinases (DUBs). DUBs have now been identified in diverse viral lineages, and their characterization is providing valuable insights into virus biology and the role of the ubiquitin system in host antiviral mechanisms. In this review, we briefly introduce the mechanisms of ubiquitination and deubiquitination, present antiviral innate immune response and its regulation by ubiquitin, and summarize the prevalence of DUBs encoded by viruses (Arteriviridae, Asfarviridae, Nairoviridae, Coronaviridae, Herpesviridae, and Picornaviridae) infecting domestic animals and poultry. It is found that these DUBs suppress the innate immune responses mainly by affecting the production of type I interferon (IFN), which causes immune evasion of the viruses and promotes their replication. These findings have important reference significance for understanding the virulence and immune evasion mechanisms of the relevant viruses, and thus for the development of more effective prevention and treatment measures.     

Collectins and cationic antimicrobial peptides of the respiratory epithelia

The respiratory epithelium is a primary site for the deposition of microorganisms that are acquired during inspiration. The innate immune system of the respiratory tract eliminates many of these potentially harmful agents preventing their colonization. Collectins and cationic antimicrobial peptides are antimicrobial components of the pulmonary innate immune system produced by respiratory epithelia, which have integral roles in host defense and inflammation in the lung. Synthesis and secretion of these molecules are regulated by the developmental stage, hormones, as well as many growth and immunoregulatory factors. The purpose of this review is to discuss antimicrobial innate immune elements within the respiratory tract of healthy and pneumonic lung with emphasis on hydrophilic surfactant proteins and beta-defensins.     

线粒体DNA在先天性免疫中的作用

线粒体是细胞内重要的细胞器,具有多种功能,是细胞的能量工厂。线粒体含有自己的遗传物质线粒体DNA,线粒体DNA因其在氧化磷酸化中的作用而广为人知。近年来,越来越多的研究表明线粒体DNA可作为先天性免疫系统的激动剂,并在病原体感染和炎性疾病的病理发展中起重要作用。线粒体DNA在进入细胞质或细胞外环境后,可以激活多种先天性免疫系统的模式识别受体,从而触发促炎细胞因子分泌和Ⅰ型干扰素反应。因此,本文就线粒体DNA激活先天性免疫的机制以及其在病原体感染和相关疾病发生发展中的作用进行讨论、总结,以期为进一步深入开展线粒体DNA在病原体感染及相关疾病中的作用及其机制研究提供理论依据。     

溶菌酶抑菌活性及检测方法研究进展

溶菌酶是广泛分布于动物、植物和微生物等生物类群中的酶类,是生物体天然免疫系统的重要组成部分,是一种非特异性的防御机制。作者结合了细菌、真菌和病毒等的生理生化特性对溶菌酶的溶菌原理进行了总结,并对其抑菌活力检测方法进行了综述,最后对其抑菌作用的应用前景进行了展望。     

牛轮状病毒UK株NSP1基因序列分析及原核表达

轮状病毒是引起多种幼龄动物及5周龄以下儿童腹泻的主要病原体。NSP1非结构蛋白是轮状病毒基因5的产物,为长约55 ku的RNA结合蛋白。现已发现NSP1蛋白是一种毒力决定因子,可颉颃宿主先天性免疫应答。参照GenBank收录的牛轮状病毒UK株序列设计并合成1对特异性引物,本试验利用RT-PCR方法扩增牛轮状病毒UK株NSP1基因,克隆入pET-28a(+)表达载体,经双酶切和测序鉴定,并利用分子生物学软件进行同源性比对分析。本试验结果显示获得的NSP1基因全长编码区序列为1 473 bp,编码491个氨基酸,与美国WC3株同源性最高。将阳性重组质粒转入E.coli Rosetta(DE3)宿主菌,经IPTG诱导表达,SDS-PAGE和Western blotting对重组蛋白进行分析,结果表明重组蛋白分子质量约为55 ku,以包涵体形式表达,可与鼠抗His-tag抗体反应。本试验成功获得牛轮状病毒UK株NSP1基因,且实现了在原核表达系统中高效表达重组蛋白,本试验结果为研究NSP1蛋白在细胞内定位与其活性之间的相互关系奠定了基础。     

Sequence Analysis and Prokaryotic Expression of NSP1 Gene of Bovine Rotavirus UK Strain

Rotavirus is a major cause of acute diarrhea in both many kinds of young animals and children under 5 years old.Rotavirus NSP1, a 55 ku RNA binding protein, is the product of gene 5, which can subvert innate immune responses and be one of virulent determinant factors.According to the sequence in GenBank, specific primers targeting to NSP1 gene were designed and the gene was amplified by RT-PCR, following by being cloned into the pET-28a(+) vector.It showed that the full length of NSP1 gene was 1 473 bp, encoding 491 amino acids.The NSP1 shared the highest identity with WC3 strain.The recombinant protein was induced in E.coli Rosetta(DE3) by IPTG and was analyzed by SDS-PAGE and Western blotting.The results revealed that NSP1 recombinant protein existed in the form of inclusion body with the molecular weight of 55 ku.The purified recombinant protein could be recognized by His-tag antibody.This study laid the foundation for further research on the relationship between the intracytoplasmic location of NSP1 protein and its activity.     

黄芪多糖对巨噬细胞天然免疫调节的研究进展

天然免疫系统是机体的第一道免疫防御屏障,在抵抗病原微生物感染的过程中起着关键性作用。如何通过药物或饲料添加剂激发畜禽天然免疫防御功能,从而最大程度地诱导机体保护性机制和减轻感染引起的炎症损伤,已成为应对当下养殖环境中病原微生物肆虐、抗生素耐药的可持续性解决方案之一。黄芪多糖(Astragalus polysaccharides, APS)作为一类生物大分子成分,是免疫活性最强的一类物质,具有免疫调节、抗病毒、抗应激、抗氧化、抗肿瘤等多种生物学作用,在临床应用中可有效提高幼龄动物的天然免疫防御功能,增强多种疫苗的保护效力及生长性能,因而其对机体天然免疫系统的调节作用及机制是近年来的研究热点。然而受产地、提取纯化方法及复杂化学结构的影响,对APS活性作用的深入研究与开发利用受到了一定的限制。作者介绍了APS现有的提取技术及存在的单糖组分,重点阐述了其对天然免疫主要效应细胞-巨噬细胞极化、功能、炎症因子表达的双向调节作用及对巨噬细胞相关Toll样受体(Toll-like receptors, TLRs)信号通路干预的研究进展,并指出了当前研究存在的问题与不足,以期为APS免疫调节机制的深入研...