Development of an oral vaccine for immunisation of rainbow trout (Oncorhynchus mykiss) against viral haemorrhagic septicaemia
Development of an oral vaccine for immunisation of rainbow trout (Oncorhynchus mykiss) against viral haemorrhagic septicaemia
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DOI：
10.1016/j.vaccine.2007.11.065
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发表时间：
2008-02-06
期刊：
影响因子：
5.5
通讯作者：
Fichtner, Dieter
中科院分区：
文献类型：
--
作者：
Adelmann, Malte;Koellner, Bernd;Fichtner, Dieter
在欧盟，病毒性出血性败血症（VHS）的根除仍然是基于消灭。由于缺乏有效的低成本疫苗，免疫预防目前未用于防治VHS。本文介绍了一种新的经口给药的鳟鱼减毒免疫方法。该疫苗由冻干的病毒包裹在聚乙二醇（PEG）中，并在低温下挤压而成。在鳟鱼的胃中，使用额外的中和和吸附碱导致疫苗颗粒周围的pH值为中性，从而保护抗原免受胃酸的侵害。在使用VHSV减毒株作为疫苗的三个动物攻毒实验中，检验了这种递送方法的体内功效。接种后，在RT-PCR后，采用半巢式PCR扩增肠道、心脏、肾脏、脾脏和血液中的VHSV mRNA。间接免疫荧光法检测肠道VHS疫苗病毒。采用实时RT-PCR技术检测口服疫苗接种后MHCⅱ类、CD4和CD8 α mrna在肠道中的表达。接种前1周和接种后5周分别用ELISA法测定抗体水平。动物在接种高毒力VHSV疫苗六周后受到攻击，并记录死亡率。实验表明，口服给药的疫苗病毒从疫苗制剂中释放出来，穿透肠道黏膜，导致MHC II类和CD4 mrna的表达水平高于对照肠道。口服疫苗接种后检测VHSV抗体。使用这种新疫苗配方进行免疫接种后，对VHSV产生了显著的保护作用。而未接种疫苗的对照组的累积死亡率达到70%，超过75%的口服接种疫苗的鱼在攻击时得到保护。(c) 2007 Elsevier Ltd.版权所有。
In the European Union Viral Haemorrhagic Septicaemia (VHS) eradication is still based on stamping out. Due to the lack of effective low cost vaccines immune prophylaxis is currently not used to combat VHS. This paper describes a new oral delivery method for immunisation of trout with attenuated virus. The vaccine consists of lyophilised virus surrounded by polyethylene glycol (PEG) and was extruded under low temperature. In the stomach of trout, the use of additional neutralising and adsorbing bases resulted in a neutral pH around the vaccine pellets, thus protecting the antigen against gastric acid. The in viva efficacy of this delivery method was examined in three animal challenge experiments using an attenuated VHS virus (VHSV) strain as a vaccine. After vaccination, VHSV mRNA in gut, heart, kidney, spleen and blood was amplified by semi-nested PCR after RT-PCR. Indirect immune fluorescence test detected VHS vaccine virus in the gut. The expression of MHC class II, CD4 and CD8 alpha mRNAs after oral vaccination was measured in gut using real-time RT-PCR. Antibody levels were measured by ELISA one week before vaccination and five weeks after vaccination. Animals were challenged six weeks after vaccination with highly virulent VHSV and mortality was recorded. The experiments showed that orally delivered vaccine virus was released from the vaccine preparation, penetrated the gut mucosa and led to higher expression levels of MHC class II and CD4 mRNAs when compared to control guts. VHSV antibodies were detected after oral vaccination. Immunisation with this new vaccine formulation was followed by a significant protection against VHSV. While the cumulative mortality in the non-vaccinated control group reached 70%, more than 75% of the orally vaccinated fish were protected upon challenge. (c) 2007 Elsevier Ltd. All rights reserved.