Host responses against the fish parasitizing ciliate Ichthyophthirius multifiliis
Host responses against the fish parasitizing ciliate Ichthyophthirius multifiliis
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DOI：
10.1016/s0304-4017(01)00487-3
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发表时间：
2001-09-12
影响因子：
2.6
通讯作者：
Dalgaard, M
中科院分区：
文献类型：
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作者：
Buchmann, K;Sigh, J;Dalgaard, M
最近的研究表明，鱼类能够对各种寄生虫产生保护性免疫反应。在这种情况下，最具特征的寄生物-宿主系统之一是寄生在一系列淡水鱼中的纤毛虫多丝小瓜虫（Ich）。特异性和非特异性宿主防御机制负责保护鱼类免受这种纤毛虫的挑战感染。特异性体液组分至少包括特异性抗体。包括的非特异性体液成分是补体旁路途径和可能的凝集素。参与特异性反应的细胞因子是B细胞和假定的T细胞。识别的非特异性效应细胞是各种白细胞。此外，杯状细胞和肥大细胞（EGC细胞）可能具有功能。NCC细胞（建议类似于哺乳动物中的NK细胞）似乎在非特异性反应中发挥作用。这一有据可查的淡水鱼对Ich的保护性反应促使了抗寄生虫疫苗的开发。事实上，已经开发了基于福尔马林杀死的寄生虫的此类产品，并发现其为接种的宿主提供令人满意的保护。然而，收集用于疫苗生产的寄生虫是极其费力的。由于寄生虫的体外繁殖仍不充分，它涉及饲养受感染的鱼。获得寄生虫保护性抗原（i抗原）的氨基酸序列及其编码DNA序列的知识是一个重大突破。这一成果使得在大肠杆菌中生产重组蛋白成为可能。初步结果表明，该产品对接种鱼有一定的保护作用。最近的工作表明，自由生活和易于培养的纤毛虫四膜虫可以转化并表达i-抗原。这条道路似乎是有希望的未来发展的疫苗对Ich。在鱼类中的一种新方法是开发DNA疫苗。在鱼类中进行了成功的DNA疫苗接种试验，以防止病毒感染，该技术还使开发针对Ich的DNA疫苗成为可能。针对Ich的免疫保护的其他方法是使用异源疫苗。因此，据报道，使用活的或杀死的（未转化的）四膜虫的浴和注射疫苗接种都能为处理过的鱼提供一定程度的保护。这种保护可以用非特异性反应来解释，这种疫苗接种类型的有效性和持续时间应进一步评估。(C)2001爱思唯尔科技有限公司。保留所有权利。
Recent studies have shown that fish are able to mount protective immune responses against various parasites. One of the best characterized parasite-host system in this context is the ciliate Ichthyophthirius multifiliis (Ich) parasitizing a range of freshwater fishes. Both specific and non-specific host defence mechanisms are responsible for the protection of fish against challenge infections with this ciliate. The specific humoral components comprise at least specific antibodies. The non-specific humoral elements included are the alternative complement pathway and probably lectins. Cellular factors involved in the specific response are B-cells and putative T-cells. The non-specific effector cells recognized are various leukocytes. In addition, goblet-cells and mast cells (EGC-cells) may have a function. The NCC-cell (suggested analogue to NK-cells in mammals) seems to play a role in the non-specific response. This well documented protective response in freshwater fishes against Ich has urged the development of anti-parasitic vaccines. Indeed, such products based on formalin killed parasites have been developed and found to offer the vaccinated host a satisfactory protection. However, the collection of parasites for vaccine production is extremely laborious. It involves keeping infected fish due to the fact that in vitro propagation of the parasite is still insufficiently developed. Gaining knowledge of amino acid sequences and its encoding DNA-sequences for the protective antigens (i-antigens) in the parasite was a major breakthrough. That achievement made it possible to produce a recombinant protein in E. coli and preliminary results indicated a certain protection of fish vaccinated with this product. Recent work has shown that the free-living and easily cultivated ciliate Tetrahymena can be transformed and express the i-antigen. This path seems to be promising for future development of vaccines against Ich. A novel approach in fish is the development of DNA-vaccines. Successful DNA-vaccination trials have been conducted in fish against viral infections and the technology also makes it possible to develop a DNA-vaccine against Ich. Other approaches to immuno-protection against Ich have been the use of heterologous vaccines. Thus, both bath and injection vaccination using live or killed (un-transformed) Tetrahymena has been reported to offer treated fish a certain level of protection. Such protection could be explained by non-specific reactions and the efficacy and duration of this vaccination type should be further evaluated. (C) 2001 Elsevier Science B.V. All rights reserved.