Differential immune response of rainbow trout (Oncorhynchus mykiss) at early developmental stages (larvae and fry) against the bacterial pathogen Yersinia ruckerie
Differential immune response of rainbow trout (Oncorhynchus mykiss) at early developmental stages (larvae and fry) against the bacterial pathogen Yersinia ruckerie
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DOI：
10.1016/j.dci.2011.08.014
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发表时间：
2012-02-01
影响因子：
2.9
通讯作者：
Buchmann, Kurt
中科院分区：
文献类型：
--
作者：
Chettri, Jiwan K.;Raida, Martin K.;Buchmann, Kurt
先天免疫因素对幼鱼的生存起着至关重要的作用，特别是在适应性免疫尚未完全发育的生命早期阶段。在本研究中，我们研究了虹鳟鱼（Oncorhynchus mykiss）幼虫和鱼苗在发育早期的免疫反应。我们将孵化后 17 天和 870 天的幼虫和鱼苗（孵化后 152 度和 1118 度天；平均重量分别为 70 和 770 毫克）暴露于细菌病原体鲁氏耶尔森菌 (Yersinia ruckeri) 中，通过沐浴挑战 4 小时。在暴露后 4、24、72 和 96 小时采集样本进行 qPCR 和免疫组织化学分析，以阐明这些幼鱼所产生的免疫反应。尽管受感染的幼虫在暴露后 48 小时表现出口腔区域充血和身体背侧炎症，但幼虫没有表现出死亡。基因表达研究表明，暴露后 24 小时，受感染的幼虫中 iNOS 和 IL-22 上调，但大多数研究的基因在受感染和未感染的幼虫之间没有显示出任何差异。免疫组织化学研究表明，感染和未感染幼虫的鳃中 IgT 分子高表达，胸腺中 CD8 阳性细胞高表达。相比之下，虹鳟鱼苗感染鲁氏耶氏菌后，累积死亡率为 74%。与未感染的对照相比，感染鱼苗中细胞因子（IL-1β、TNF-α、IL-22、IL-8 和 IL-10）、急性期蛋白（SAA、铁调素、转铁蛋白和前小脑蛋白）、补体因子（C3、C5 和因子 B）、抗菌肽（cathelicidin-2）和 iNOS 的高表达。通过免疫组织化学检测感染和未感染鱼苗鳃中的 IgT 分子和甘露糖结合凝集素。该研究表明，生命早期阶段（卵黄囊幼虫）仅上调一些基因，并表明幼虫通过转录水平的基因调控发起免疫反应的能力有限。根据观察到的细菌清除率和死亡率的缺乏，可以推测幼虫可能被不同免疫因子的保护罩覆盖，提供针对多种病原体的保护。然而，较大鱼苗的易感性增加表明 Y. tucker( 可能利用一些免疫元件进入幼鱼。受感染幼鱼中 iNOS 和 IL-22 的上调表明这些分子在早期发育阶段的免疫反应中发挥着重要作用。幼鱼中 IgT 抗体致密地覆盖鳃丝表面，表明该抗体作为先天性抗体发挥着作用。 早期发育阶段的免疫因子。 (C) 2011 Elsevier Ltd. 保留所有权利。
Innate immune factors play a crucial role in survival of young fish especially during early stages of life when adaptive immunity is not fully developed. In the present study, we investigated the immune response of rainbow trout (Oncorhynchus mykiss) larvae and fry at an early stage of development. We exposed 17 and 870 days post hatch larvae and fry (152 and 1118 degree days post hatch; avg. wt. 70 and 770 mg, respectively) to the bacterial pathogen, Yersinia ruckeri for 4 h by bath challenge. Samples were taken at 4, 24, 72 and 96 h post exposure for qPCR and immunohistochemical analyses to elucidate the immune response mounted by these young fish. Larvae showed no mortality although infected larvae at 48 h post exposure showed hyperaemia in the mouth region and inflammation on the dorsal side of the body. Gene expression studies showed an up-regulation of iNOS and IL-22 in infected larvae 24 h post exposure but most of the investigated genes did not show any difference between infected and uninfected larvae. Immunohistochemical studies demonstrated a high expression of IgT molecules in gills and CD8 positive cells in thymus of both infected and uninfected larvae. Infection of rainbow trout fry with Y. ruckeri, in contrast, induced a cumulative mortality of 74%. A high expression of cytokines (IL-1 beta, TNF-alpha, IL-22, IL-8 and IL-10), acute phase proteins (SAA, hepcidin, transferrin and precerebellin), complement factors (C3, C5 and factor B), antimicrobial peptide (cathelicidin-2) and iNOS was found in infected fry when compared to the uninfected control. IgT molecules and mannose binding lectins in gills of both infected and uninfected fry were detected by immunohistochemistry. The study indicated that early life stages (yolk-sac larvae), merely up-regulate a few genes and suggests a limited capacity of larvae to mount an immune response by gene regulation at the transcriptional level. Based on the observed clearance of bacteria and lack of mortality it could be speculated that larvae may be covered by protective shield of different immune factors providing protection against broad range of pathogens. However, I he increased susceptibility of older fry suggests that Y. tucker( may utilize some of the immune elements to enter the naive fish. The up-regulation of iNOS and IL-22 in the infected larvae implicates an important role of these molecules in immune response at early developmental stages. A dense covering of surfaces of gill filaments by IgT antibody in the young fish suggest a role of this antibody as innate immune factor at early developmental stages. (C) 2011 Elsevier Ltd. All rights reserved.