中文摘要：

天然免疫（innate immunity）是基于对病原微生物成分的非克隆性识别而启动的快速防御反应。天然免疫系统可通过胚系编码的模式识别受体（pattern-recognition receptors,PRR）识别恒定不变的病原基元,即病原相关分子模式（pathogen-associated molecular patterns,PAMPs）,启动信号级联转导,最终PRRs信号激活宿主免疫和前炎性基因的表达,引发针对所识别病原的免疫反应。目前PRRs主要分为5类,即C-型Lectins、Toll样受体（Toll-like receptors,TLRs）、视黄酸诱导基因I样受体（retinoic acid inducible gene I-like receptors,RLRs）、包含核苷酸结合区和亮氨酸富集区蛋白（the nucleotide-binding domain,leucine-rich repeatcontaining proteins,NLRs,也称NOD样受体）和最近发现的AIM样受体（absent in melanoma（AIM）-like receptors,ALRs）。近年来,随着5种鱼类基因组序列草图的完成,大量鱼类PRRs基因被发现,一些PRRs的配体特异性及其相关信号途径正在逐渐明晰。为此,将对鱼类Toll样受体（TLRs）、视黄酸诱导基因I样受体（RLRs）和NOD样受体（NLRs）的研究进展进行综述。

英文摘要：

Innate immunity initiates immediate defense mechanisms on the basis of non-clonal recognition of microbial components.By the use of germ-line encoded PRRs,the innate immune system is capable of detecting invariant pathogen motifs termed pathogen-associated molecular patterns（PAMPS） that are distinct from host encoded proteins or products released from dying cells.Based on ligand recognition,all of these receptors depend upon the interaction of specific bridging proteins to initiate a cascade that results in signaling events.The PRR signaling eventually activates the expression of multiple host immune and pro-inflammatory genes and direct an immune response to the detected pathogen.The PRRs currently are classified into five major groups： the C-type lectins,Toll-like receptors（TLRs）,RIG I-like receptors（RLRs）,NOD-like receptors（NLRs）,and the recently designated absent in melanoma（AIM）-like receptors（ALRs）.Recently,the emergence of genomics research and draft genome sequences of five bony fish species resulted in the discovery of many PRR genes in teleosts.The ligand specificity of some PRRs and their related signaling cascades have been clarifying.In this paper,recent research progress on fish TLRs,RLRs and NLRs has been reviewed.