Piazzón C, Lamas J, Castro R, Budiño B, Cabaleiro S, Sanmartín M, Leiro J
Departamento de Biología Celular y Ecología, Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Fish Shellfish Immunol. 2008 Oct;25(4):417-24. doi: 10.1016/j.fsi.2008.05.012. Epub 2008 Jun 14.
The protection induced in turbot by inactivated vaccines containing either of two isolates (I(1) and C(1)) of the scuticociliate parasite Philasterides dicentrarchi, which causes important mortalities in turbot cultures, was evaluated in the present study. The results obtained after challenging the fish with the two isolates show that vaccination protected fish only against the homologous isolate, but did not confer cross-protection. The two isolates constitute two serotypes, as shown in the immobilization tests with mouse and turbot anti-I(1) and anti-C(1) antisera, in which only the homologous antisera immobilized the ciliates. ELISA assays, using total antigen free of proteases (TAWP), cytosolic antigens (CYA), ciliar antigens (CA) or membrane protein fraction (MPF), were also carried out. Differences in the levels of antibodies produced in mouse against the homologous and heterologous antigens were observed; these differences were significantly different when the antigen preparations used in the ELISA were TAWP, CYA or CA. Nevertheless, ELISA assays using turbot sera against TAWP did not show significant differences in the levels of antibodies against the homologous and heterologous antigens. Antigenic cross-reactivity was also detected in the Western blot assays, as well as significant differences in the patterns of antigenic recognition in the two isolates - in both reduced and non-reduced TAWP antigens, but which was noteworthy when mouse antisera were used. The results obtained in the present study demonstrate for the first time the existence of serotypes of the ciliate parasite of turbot Philasterides dicentrarchi that display clear antigenic differences, which must be taken into consideration in the future development of a vaccine against scuticociliatosis.
本研究评估了由包含盾纤毛虫寄生虫双盘藻（Philasterides dicentrarchi）的两种分离株（I(1)和C(1)）之一的灭活疫苗在大菱鲆中诱导的保护作用，这种寄生虫在大菱鲆养殖中会导致重要的死亡。在用这两种分离株对鱼进行攻毒后获得的结果表明，疫苗接种仅保护鱼免受同源分离株的侵害，但没有提供交叉保护。如用小鼠和大菱鲆抗I(1)和抗C(1)抗血清进行的固定试验所示，这两种分离株构成两种血清型，其中只有同源抗血清能固定纤毛虫。还进行了酶联免疫吸附测定（ELISA），使用不含蛋白酶的总抗原（TAWP）、胞质抗原（CYA）、纤毛抗原（CA）或膜蛋白组分（MPF）。观察到小鼠针对同源和异源抗原产生的抗体水平存在差异；当ELISA中使用的抗原制剂为TAWP、CYA或CA时，这些差异具有显著意义。然而，使用大菱鲆血清针对TAWP进行的ELISA测定未显示针对同源和异源抗原的抗体水平存在显著差异。在蛋白质印迹分析中也检测到抗原交叉反应，并且在两种分离株的抗原识别模式中存在显著差异——在还原和非还原的TAWP抗原中均如此，但当使用小鼠抗血清时尤为显著。本研究获得的结果首次证明了大菱鲆的纤毛虫寄生虫双盘藻存在血清型，这些血清型表现出明显的抗原差异，在未来开发抗盾纤毛虫病疫苗时必须予以考虑。
