Kai Yu-Hsuan, Chi Shau-Chi
Institute of Zoology, National Taiwan University, Taipei, Taiwan.
Vaccine. 2008 Mar 10;26(11):1450-7. doi: 10.1016/j.vaccine.2007.12.043. Epub 2008 Feb 13.
Betanodavirus is the pathogen of viral nervous necrosis (VNN) disease that has caused mass mortality among many species of marine fish at larval stage. In this study, the efficacy of inactivated betanodavirus was evaluated by bath-immunization and bath-challenge of orange-spotted grouper (Epinephelus coioides) at early larval stage. Two kinds of chemicals were used for inactivation of the virus, and the relative percent survival (RPS) values of 0.4mM binary ethylenimine (BEI)-inactivated vaccine was revealed to be 79-95, higher than that of 0.1-0.2% formalin-inactivated vaccines (39-43). Three lengths of bath immunization time were tested, and 20 min immersion of BEI-inactivated betanodavirus at a concentration of 10(6)TICD(50)/ml was sufficient to induce high protection (RPS > 75). Protection of the BEI-inactivated vaccine was evaluated at different time post immunization, and the peak of protection was observed 30 days post vaccination, and retained for at least 3 months. The efficacies of formalin-inactivated vaccines with or without encapsulation were compared, and the result revealed that the efficacy of formalin-inactivated vaccine could be significantly improved by nano-encapsulation (RPS = 85). All these data strongly suggested that bath immunization with nano-encapsulated formalin-inactivated or BEI-inactivated betanodavirus vaccines is an effective strategy to protect grouper larvae against VNN.
神经坏死病毒是病毒性神经坏死（VNN）疾病的病原体，该疾病已导致许多海洋鱼类幼体大量死亡。在本研究中，通过对早期幼体阶段的斜带石斑鱼（Epinephelus coioides）进行浸浴免疫和浸浴攻毒，评估了灭活神经坏死病毒的效力。使用两种化学物质对病毒进行灭活，结果显示0.4mM双（2-氯乙基）胺（BEI）灭活疫苗的相对存活率（RPS）值为79-95，高于0.1-0.2%福尔马林灭活疫苗（39-43）。测试了三种浸浴免疫时间长度，将浓度为10(6)TICD(50)/ml的BEI灭活神经坏死病毒浸泡20分钟足以诱导高度保护（RPS>75）。在免疫后的不同时间评估BEI灭活疫苗的保护效果，在接种疫苗后30天观察到保护峰值，并持续至少3个月。比较了有或没有包封的福尔马林灭活疫苗的效力，结果显示纳米包封可显著提高福尔马林灭活疫苗的效力（RPS = 85）。所有这些数据强烈表明，用纳米包封的福尔马林灭活或BEI灭活神经坏死病毒疫苗进行浸浴免疫是保护石斑鱼幼体免受VNN侵害的有效策略。
