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先天免疫是宿主识别病原及消除病原感染的第一道防线。模式识别受体是参与识别病原入侵的主要分子，主要包括Toll样受体、RIG-I样受体、NOD样受体和C型凝集素受体等。模式识别受体在识别病原相关分子模式后，激活机体的先天免疫信号通路，诱导炎症细胞因子和干扰素的产生，从而启动抵抗病原入侵的免疫应答。越来越多的证据表明，免疫应答的激活、维持和终止受到了严格的调节，使机体在保持一定免疫强度的同时避免产生过度的免疫反应。microRNA是一类长度为18～23 nt的微小非编码RNA，是鱼类先天免疫应答网络中的重要调控因子。近年来，microRNA在鱼类免疫学领域已开展了大量的研究，但缺乏对其进行及时地全面性的总结。本文综述了近年来miRNA在鱼类先天免疫反应中的研究进展，以期为鱼类的分子抗病育种及疾病防控研究提供一些思路。 相似文献
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Pro‐inflammatory caspase‐1 activation during the immune response in cells from rainbow trout Oncorhynchus mykiss (Walbaum 1792) challenged with pathogen‐associated molecular patterns 
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下载免费PDF全文 In response to pathogens, the higher vertebrate innate immune system activates pro‐inflammatory caspase‐1 which is responsible for the processing and secretion of several important cytokines involved in the host's defence against infection. To date, caspase‐1 has been described in few teleost fish, and its activity has been demonstrated through substrate cleavage and inhibition by pharmacological agents. In this study, the detection of the active form of caspase‐1 during the immune response in salmonid fish is described, where two antibodies were produced. These antibodies differentially recognize the structural epitopes of the inactive pro‐caspase‐1 and the processed active form of the caspase. Firstly, caspase‐1 activation was demonstrated in vitro by ELISA, Western blotting and immunocytochemistry in rainbow trout macrophages exposed to different pathogen‐associated molecular patterns plus the pathogen Aeromonas hydrophila. This activity was clearly abrogated by a caspase inhibitor and seems to be unrelated to IL‐1β secretion. Caspase‐1 activation was then validated in vivo in gill cells from fish challenged with Aeromonas salmonicida. These results represent the first demonstration of caspase‐1 activation in salmonids, and the first evidence of the putative regulatory role which this protease plays in inflammatory response in this fish group, as described for some other teleosts and mammals. 相似文献
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In aquaculture, antibiotics are the traditional treatment used against bacterial infections. However, their use has increasingly come into question given their effects on fish and, possibly, on human health. Consequently, there is interest in developing alternative treatments aimed at stimulating the innate immune response of fish, which is the first line of defense against pathogens. In relation to this, the Toll-like receptors (TLR) aid in the selective identification of pathogens. The present study evaluated immunostimulatory activity of prolactin (PRL) hormone on expression levels of TLR1, 9, and 22, MyD88, and IL-1β during in vitro infection with the fish pathogen Piscirickettsia salmonis, in primary cultures of Oncorhynchus mykiss head kidney cells. Results indicated that PRL increased expression of TLRs and MyD88 during the first hours of bacterial infection, while a constant increase in expression was found for IL-1β. These findings suggest that PRL indirectly modulates expression of TLRs by activating expression of suppressors of cytokine signaling, thereby regulating immune response over long periods of time during bacterial infection. 相似文献
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Nucleotide‐binding and oligomerization domain (NOD)‐like receptors in teleost fish: Current knowledge and future perspectives 下载免费PDF全文
下载免费PDF全文 Liang Zhang Zhuying Gao Li Yu Bo Zhang Jing Wang Jun Zhou 《Journal of fish diseases》2018,41(9):1317-1330
Nucleotide‐binding and oligomerization domain (NOD)‐like receptors (NLRs) are a group of intracellular pathogen recognition receptors (PRRs) that play key roles in pathogen recognition and subsequent activation of innate immune signalling pathways. Expressions of several NLR subfamily members, including NOD1, NOD2, NLR‐C3, NLR‐C5 and NLR‐X1 have been reported in many different teleost fish species. These receptors are activated by a variety of ligands, including lipopolysaccharides (LPS), peptidoglycans (PGN) and polyinosinic‐polycytidylic acid [Poly(I:C)]. Synthetic dsRNA and bacterial or viral infections are known to stimulate these receptors both in vitro and in vivo. In this review, we focus on the identification, expression and function of teleost NLRs in response to bacterial or viral pathogens. Additionally, NLR ligand specificity and signalling pathways involved in the recognition of bacterial or viral stimuli are also summarized. This review focuses on current knowledge in this area and provides future perspectives regarding topics in need of additional investigation. Understanding the response of innate immune system to bacterial or viral infections in diverse species could inform the development of more effective therapies and vaccines. 相似文献
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采用RACE技术克隆得到三疣梭子蟹(Portunus trituberculatus)TLRs家族的一个新基因,将其命名为Pt Toll4。该基因c DNA全长为4276 bp,5?和3?非编码区分别为339 bp和1252 bp,编码一个含有895个氨基酸、分子量为102.5 k Da、理论等电点为6.03的蛋白质。Pt Toll4蛋白是一个跨膜蛋白,存在胞外区LRR、LRRCT结构域及保守的胞内区TIR结构域。同源性及系统进化分析显示,Pt Toll4氨基酸序列与中华绒螯蟹(Eriocheir sinensis)Es Toll2的同源性最高,为61%。实时荧光定量PCR结果显示,Pt Toll4基因在血细胞中的表达量最高,在肝胰腺中的表达量最低。利用副溶血弧菌(Vibrio parahemolyticus)和对虾白斑综合征病毒(WSSV)对三疣梭子蟹进行注射感染,结果显示,经WSSV感染后,Pt Toll4基因在血细胞中的表达量显著提高,在6 h时出现峰值,为对照组的5.03倍(P0.01)。经副溶血弧菌感染后,Pt Toll4基因仅在48 h略微出现上调,其余时间点与对照组无显著差异。由此推测,Pt Toll4基因在三疣梭子蟹应答WSSV的免疫过程中发挥了重要功能。此外发现,低盐胁迫显著抑制了Pt Toll4基因在三疣梭子蟹血细胞中的表达,这可能是导致低盐环境下三疣梭子蟹等甲壳类动物免疫力下降的原因之一。由此推测,Pt Toll4基因在三疣梭子蟹先天免疫过程中发挥了重要功能,本研究为深入开展三疣梭子蟹和其他甲壳动物的免疫调控机理研究提供了数据支持。 相似文献
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Buchmann K 《Journal of fish diseases》2012,35(9):623-635
Vertebrates mount a series of immune reactions when invaded by helminths but antihelmintic immune strategies allow, in many cases, the first invaders of the non-immune host to survive for prolonged periods, whereas subsequent larval invaders of the same parasite species face increased host resistance and thereby decreased colonization success. This concomitant immunity may represent a trade-off between adverse side effects (associated with killing of large helminths in the host tissue) and the need for future protection against invasion. Encapsulation and isolation of large live endoparasitic larvae may be associated with less pathology compared to coping with excess dead parasite tissue in host organs. Likewise, live adult nematodes may be accepted in tissues at a certain activity level for the same reasons. Various host cell receptors bind helminth molecules after which signal-transducing events lead to mobilization of specific reaction patterns depending on the combination of receptors and ligands involved. Both innate and adaptive responses (humoral and cellular) are prominent actors, but skewing of the Th1 lymphocyte response towards a Th2 type is a characteristic element of antihelminthic responses in mammalian hosts. Similar patterns may be expected also to occur in at least some fish species, such as salmonids, producing relevant cytokines, MHCII and CD4+ cells required for these lymphocyte subpopulations. Atlantic cod, Gadus morhua L., is without these immunological elements that indicate that alternative reaction pathways exist in at least some fish groups. Recent achievements within teleost immunology have made it possible to track these host responses in fish and the present work outlines the main immune reactions in fish against helminths and suggests three experimental fish models for exploration of these immune pathways in fish infected with nematodes. 相似文献
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细胞因子是一类由多种细胞合成或分泌的可溶性蛋白与多肽物质,具有调节多种细胞生理功能的作用.抗细胞凋亡因子(DAD1)是一种内源性细胞凋亡抑制基因.同种移植炎症因子(AIF-1)是一种由干扰素r诱导的钙离子结合蛋白.本文概述了DAD1和AIF-1的结构特点、功能表达、生物学作用及在水产动物中的最新研究进展,旨在为水产动物细胞因子的研究和有效应用提供参考资料. 相似文献
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Toll样受体(Toll-like receptor, TLR)是一种古老的先天性免疫受体,参与病原体相关分子模式识别,对维持免疫稳态和预防感染至关重要。本研究克隆和鉴定了卵形鲳鲹(Trachinotus ovatus) TLR13基因(命名为ToTLR13),其开放阅读框(ORF)为1 269 bp,编码422个氨基酸,等电点为8.13。保守结构域分析显示,ToTLR13含有跨膜结构域(TM)、LRR结构域和TIR结构域,符合TLR家族的典型特征。通过建立TLR13保守域三级结构发现,ToTLR13与小鼠(Mus musculus)和大黄鱼(Larimichthys crocea) TLR13功能结构域的蛋白三级结构具有较高重叠性。多序列比对显示,ToTLR13与其他硬骨鱼TLR13具有较高的相似性,与其他纲物种的序列相似性较低。系统进化树结果显示,ToTLR13与硬骨鱼TLR13聚在一起,其中与鞍带石斑鱼(Epinephelus lanceolatus)最为接近,与哺乳动物、两栖类和贝类相分离。实时荧光定量PCR (Real-time fluorescence quantitative PCR, RT-qPCR)分析显示,ToTLR13在健康卵形鲳鲹的心、鳃、肾、头肾、肝、脾、脑和肌肉中普遍表达,其中鳃的表达量最高,其次是脾。ToTLR13在其鳃、脾、肝和肾免疫相关组织中的表达情况呈现出不同程度的上调,提示其经无乳链球菌(Streptococcus agalactiae)和溶藻弧菌(Vibrio alginolyticus)免疫刺激后可能激活了炎症反应,启动了先天性免疫反应。亚细胞定位显示,ToTLR13定位于A549细胞质。本研究表明,ToTLR13在抵御病原菌免疫应答过程中可能发挥重要的作用,研究结果可为阐明脊椎动物TLRs的功能进化史提供基础资料。 相似文献
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Phenotypical parameters as a tool to evaluate the immunostimulatory effects of laminarin in Oncorhynchus mykiss 下载免费PDF全文
下载免费PDF全文 Byron Morales‐Lange Jörn Bethke Paulina Schmitt Luis Mercado 《Aquaculture Research》2015,46(11):2707-2715
Laminarin is a β‐glucan from the brown algae Laminaria digitata (J.V. Lamour), which can activate innate immune responses. With the aim of developing a strategy to evaluate specific phenotypical parameters of the effects of laminarin in trout innate immunity, we (i) fed fish with laminarin‐supplemented diet (0.2 g kg?1 day?1) for 21 days and (ii) treated fish with a single dose of intraperitoneal injected laminarin (0.08 g kg?1 fish). The evaluation of cellular and humoral immune parameters was established at phenotypic level by the phagocytic activity of headkidney macrophages and detection of inflammatory cytokines in head kidney and gill tissue by indirect ELISA. Results showed that both delivery methods of laminarin produce an increase in the phagocytic activity in head kidney macrophages and a significant increase in the production of TNFα and IL‐8 in gill tissue at day 21. Additionally, some of these parameters were significantly correlated (P < 0.025), which places them as new potential combined markers to detect activation of trout defense mechanisms by laminarin. These results highlight the importance of developing new protocols to quantitate immune parameters, in order to evaluate immunostimulants in fish farming. 相似文献
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Toll样受体(Toll-like receptor,TLR)是模式识别受体家族(PRR)中重要的一员,它可以特异地识别病原体相关的分子模式(PAMP),激活信号级联、诱发固有免疫反应,在抵御病原微生物过程中发挥重要作用。TLRs最早在果蝇胚胎中发现,是一类进化高度保守的免疫受体家族,在果蝇及脊椎动物中研究得较为透彻。海洋贝类具有较高的经济价值及重要系统进化地位,近年来,大量贝类的Toll样受体及信号通路相关因子被发现。本文综述了Toll样受体的结构、信号通路和海洋贝类TLR及信号通路相关因子的研究进展,有助于丰富海洋贝类固有免疫理论研究。 相似文献
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鱼类免疫应答机制研究进展 总被引：1，自引：0，他引：1
鱼类免疫应答可以分为固有免疫和适应性免疫,但固有免疫发挥主要作用。固有免疫对病原体的识别是通过模式识别受体PRR与病原相关分子模式PAMP的相互结合实现,这与哺乳类相似。但为适应水生生活,鱼类固有免疫对PAMP的识别范围更广,免疫应答的启动条件更低。固有免疫的效应细胞主要是单核/巨噬细胞、嗜中性粒细胞、自然杀伤细胞等,具有吞噬和杀伤功能,还可分泌多种免疫相关的细胞因子,介导发生炎症反应。适应性免疫中,T淋巴细胞通过抗原提呈细胞分解吸收抗原,由主要组织相容性复合物(MHC)类分子递送到细胞表面才能识别。B淋巴细胞分泌产生以免疫球蛋白Ig M为主的抗体分子,而发挥抗体中和作用及免疫调理作用的Ig G在鱼类中比较少见,说明鱼类抗体的免疫功能还处于较低水平。本文综述了近二十年内鱼类免疫应答机制的相关研究进展,为进一步了解鱼类免疫应答机制提供参考。 相似文献
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Dietary effects of soybean products on gut microbiota and immunity of aquatic animals: A review 下载免费PDF全文
下载免费PDF全文 Soybean meal (SBM) is one of the most commonly used vegetable ingredient to replace fish meal in fish diets. However, SBM is limiting in some essential amino acids and contains numerous antinutritional factors and antigens that can affect intestinal microbiota and innate immune system in several finfish species and crustaceans and compromise health. The impact of SBM on health and gut microbiota of aquatic animals is not only affected by SBM in general, but also on the degree of treatment of the meal and exposure. Recently, many studies are actively seeking ways to complement or balance those adverse responses induced by high inclusion of SBM in aquaculture diets. These include advanced processing and mixture of feed with other feed components to balance antinutritional factors. The impact of dietary soybean oil on gut microbiota has also been investigated but to a lesser extent than SBM. As the gastrointestinal tract has been suggested as one of the major routes of infection in finfish species and crustaceans, the effect of soybean products on the gut microbiota is important to investigate. Several studies have focus on supplementation of SBM on the adverse responses of the innate immune system as immunological mechanisms are likely involved in the underlying pathology. However, the precise cause of the inflammatory process has not yet been clarified, even though some investigations have suggested that alcohol‐soluble antinutritional factors, especially soy saponins, are potential causative factors. Possible interactions between soybean products and innate immune system in several finfish species and crustaceans are discussed. 相似文献
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中国明对虾C 型凝集素基因(Fclectin)的重组表达及活性分析 总被引：1，自引：1，他引：0
研究拟通过分析对虾C型凝集素的活性特点,探讨其在对虾先天免疫应答过程中的潜在功能以及在养殖生产实践中的应用。实验利用原核表达系统对中国明对虾C-型凝集素基因的两个串联的糖识别结构域(carbohydrate recognition domain,CRD)进行了重组表达,并通过纯化复性获得了重组目的蛋白(rFclectin-CRD1和rFclectin-CRD2)。活性分析结果显示,重组目的蛋白对多种病原菌有凝集和抑制生长的作用,并且具有Ca2+依赖活性;其凝集活性可被半乳糖、肽聚糖、脂多糖等多种病原相关分子模式所抑制,研究结果证实,Fclectin是一种典型的C-型凝集素,它可能作为中国明对虾先天免疫中重要的模式识别受体,在一定程度上参与了机体应答病原微生物的防御过程。 相似文献
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Probiotics,immunostimulants, plant products and oral vaccines,and their role as feed supplements in the control of bacterial fish diseases 下载免费PDF全文
下载免费PDF全文 There is a rapidly increasing literature pointing to the success of probiotics, immunostimulants, plant products and oral vaccines in immunomodulation, namely stimulation of the innate, cellular and/or humoral immune response, and the control of bacterial fish diseases. Probiotics are regarded as live micro‐organisms administered orally and leading to health benefits. However, in contrast with the use in terrestrial animals, a diverse range of micro‐organisms have been evaluated in aquaculture with the mode of action often reflecting immunomodulation. Moreover, the need for living cells has been questioned. Also, key subcellular components, including lipopolysaccharides, have been attributed to the beneficial effect in fish. Here, there is a link with immunostimulants, which may also be administered orally. Furthermore, numerous plant products have been reported to have health benefits, namely protection against disease for which stimulation of some immune parameters has been reported. Oral vaccines confer protection against some diseases, although the mode of action is usually linked to humoral rather than the innate and cellular immune responses. This review explores the relationship between probiotics, immunostimulants, plant products and oral vaccines. 相似文献
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Molecular cloning of sea perch (Lateolabrax japonicus) TLR1 and analysis of its expression pattern after stimulation with various bacteria 下载免费PDF全文
下载免费PDF全文 Fuxiang Li Pengfei Wang Chao Zhao Sigang Fan Lulu Yan Chengyang Wang Lihua Qiu 《Aquaculture Research》2018,49(7):2455-2465
Toll‐like receptors (TLRs) play an indispensable role in fish immunity, being involved in pathogen recognition and the triggering of immune reactions. Here, a member of the TLR family, TLR1, from Lateolabrax japonicus was characterized and its expression pattern and intracellular localization were analysed. The full‐length LjTLR1 cDNA (2,755 bp) was found to encode a polypeptide of 827 amino acids. The deduced amino acid sequence contained three main structural domains: an extracellular leucine‐rich repeat domain, a transmembrane domain and a Toll/IL‐1 receptor domain. Tissue distribution analysis indicated that LjTLR1 was expressed in all of the examined tissues to varying degrees, with the highest levels being measured in the head kidney. In order to assess the antibacterial functions of LjTLR1 during infection, the pathogenic bacteria Vibrio harveyi and Streptococcus agalactiae were used. LjTLR1 was significantly upregulated in the three immune organs (the head kidney, spleen and liver) following bacterial stimulation, and its expression was detected 6 hr after initial exposure. In mRNA in situ hybridization experiments, positive signals were more numerous in the treatment group than the control group, verifying the expression patterns observed. Assessment of the intracellular localization of LjTLR1 revealed it to be present in the cytoplasm. These results indicate the potential role of LjTLR1 in immune responses to bacterial infection. This study enriches our knowledge of L. japonicus immune genes and provides a theoretical basis for further research concerning the antibacterial functions of fish TLRs during infection. 相似文献
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Cloning and expression analysis of innate immune genes from red sea bream to assess different susceptibility to megalocytivirus infection 下载免费PDF全文
下载免费PDF全文 As suggested by the Office International des Epizooties (OIE), fishes belonging to the genus Oplegnathus are more sensitive to megalocytivirus infection than other fish species including red sea bream (Pagrus major). To assess the roles of the innate immune response to these different susceptibilities, we cloned the genes encoding inflammatory factors including IL‐8 and COX‐2, and the antiviral factor like Mx from red sea bream for the first time and performed phylogenetic and structural analysis. Analysed expression levels of IL‐1β, IL‐8 and COX‐2 and the antiviral factor like Mx genes performed with in vivo challenge experiment showed no difference in inflammatory gene expression or respiratory burst activity between red sea bream and rock bream (Oplegnathus fasciatus). However, the Mx gene expression levels in red sea bream were markedly higher than those in rock bream, suggesting the importance of type I interferon (IFN)‐induced proteins, particularly Mx, during megalocytivirus infection, rather than inflammation‐related genes. The in vitro challenge experiments using embryonic primary cultures derived from both fish species showed no difference in cytopathic effects (CPE), viral replication profiles, and inflammatory and Mx gene expression pattern between the two fish species. 相似文献
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Bethke J Rojas V Berendsen J Cárdenas C Guzmán F Gallardo JA Mercado L 《Journal of fish diseases》2012,35(5):379-388
The main cellular responses of innate immunity are phagocytic activity and the respiratory burst, which produces a high amount of reactive oxygen species. Natural killer enhancing factor (NKEF) belongs to the peroxiredoxin family that has an antioxidant function and enhances cytotoxic cell activity. This molecule may play a key role in macrophage and cytotoxic cell communication during the innate immune response of fish against pathogens. In fish, the NKEF gene has been characterized in some species as showing an up-regulation in infected fish, suggesting a trigger effect upon NK-like cells. To detect and localize this molecule in salmonids at protein level, a monospecific polyclonal antibody was generated. A probable NKEF-like protein epitope region was identified and characterized using bioinformatic tools, and the sequence was chemically synthesized using Fmoc strategy, analysed by RP-HPLC and its molecular weight confirmed by mass spectrometry. The synthetic peptide was immunized and antibodies from ascitic fluid were obtained. The resulting antibody is a versatile tool for detecting NKEF by different immune techniques such as ELISA, Western blotting and immunohistochemistry. Analysis of NKEF-like protein is a useful method for characterizing immune properties of this molecule in fish during response to pathogens. 相似文献