Rubio-Godoy Miguel, Tinsley Richard C
School of Biological Sciences, University of Bristol, BS8 1UG, UK.
Parasitol Res. 2004 Mar;92(5):367-74. doi: 10.1007/s00436-003-1056-6. Epub 2004 Jan 22.
Rainbow trout (Oncorhynchus mykiss) were experimentally infected by continuous or single exposure with the monogenean Discocotyle sagittata. To determine whether immunity follows primary infection, fish were exposed to a secondary challenge by one of two modes: (1) primary infections were cleared with praziquantel (PZQ) and hosts re-infected with 100 oncomiracidia; (2) parasites were allowed to reach maturity and hosts super-infected with 100 oncomiracidia. Fish challenged after initial continuous exposure developed significant partial resistance to re-infection, carrying burdens 35% lower than controls. PZQ treatment controls demonstrated that the drug did not account for the protection observed. Single exposure did not significantly modify the outcome of secondary challenges. Super-infection experiments suggested that no concomitant immunity develops. No correlation was found between initial burdens and the outcome of secondary challenges in the same individual. Significantly elevated anti-D. sagittata antibodies were detected in infected fish, but there was no correlation between immunoglobulin levels and parasite burdens.
虹鳟（Oncorhynchus mykiss）通过连续或单次暴露于单殖吸虫箭盘吸虫（Discocotyle sagittata）进行实验性感染。为了确定初次感染后是否产生免疫力，鱼类通过以下两种方式之一接受二次攻击：（1）用吡喹酮（PZQ）清除初次感染，然后用100个纤毛幼虫重新感染宿主；（2）让寄生虫发育成熟，然后用100个纤毛幼虫对宿主进行超感染。初次连续暴露后受到攻击的鱼类对再次感染产生了显著的部分抗性，其感染负荷比对照组低35%。PZQ治疗对照组表明，该药物不能解释所观察到的保护作用。单次暴露并未显著改变二次攻击的结果。超感染实验表明没有产生伴随免疫。在同一个体中，初次感染负荷与二次攻击的结果之间没有相关性。在感染的鱼类中检测到抗箭盘吸虫抗体显著升高，但免疫球蛋白水平与寄生虫负荷之间没有相关性。
