Marine Immunobiology Laboratory, Department of Earth and Marine Sciences, University of Palermo, Viale delle Scienze, Ed.16, 90128, Palermo, Italy.
Department of Cellular Biology and Histology, Faculty of Biology, University of Murcia, Campus of International Excellence, Campus Mare Nostrum, 30100, Murcia, Spain.
Fish Shellfish Immunol. 2021 Jul;114:330-339. doi: 10.1016/j.fsi.2021.05.011. Epub 2021 May 18.
The external mucus layer that covers fish skin contains numerous immune substances scarcely studied that act as the first line of defence against a broad spectrum of pathogens. This study aimed to characterize and describe for the first time several humoral immune defence parameters in the skin mucus of the European eel (Anguilla anguilla) after intraperitoneal injection with Vibrio anguillarum or Tenacibaculum soleae. This study evaluated several immune-related enzymes and bactericidal activity against fish pathogenic bacteria in the skin mucus of European eels at 24, 48, and 72 h post-challenge. The results demonstrated that European eel skin mucus showed significant increments in peroxidase and lysozyme activity at 48 and 72 h after V. anguillarum challenge, compared to other experimental groups. In the case of antiprotease activity, an increase was observed at 24 h in the skin mucus of fish challenged with V. anguillarum compared to unchallenged fish, while this activity was undetected at 48 and 72 h. In contrast, protease activity had decreased at 48 and 72 h in the skin mucus of fish challenged with V. anguillarum compared to the unchallenged group. Regarding bactericidal activity, a high growth capacity of T. soleae was observed in the skin mucus of all experimental groups. Interestingly, the skin mucus from fish challenged with V. anguillarum exhibited increased bactericidal activity against this bacterium at 48 h, compared to unchallenged fish. Finally, severe histopathological alterations were observed in the gills and liver at the end of the trial (72 h), whereas the skin showed only an overspread presence of goblet cells in the challenged fish compared to unchallenged fish. The present results may give new insights into the mucosal immune system of this primitive species with potential applications in aquaculture.
覆盖鱼类皮肤的外黏液层含有许多尚未被充分研究的免疫物质，这些物质是抵御广谱病原体的第一道防线。本研究旨在首次对经腹腔注射鳗弧菌或灿烂弧菌后，欧洲鳗鲡皮肤黏液中的几种体液免疫防御参数进行特征描述。本研究在 challenged 后 24、48 和 72 h 时，评估了欧洲鳗鲡皮肤黏液中的几种与免疫相关的酶和对鱼类致病性细菌的杀菌活性。结果表明，与其他实验组相比，欧洲鳗鲡皮肤黏液中的过氧化物酶和溶菌酶活性在 challenged 后 48 和 72 h 时显著增加。就抗蛋白酶活性而言， challenged 鳗鲡的皮肤黏液在 challenged 后 24 h 时比未 challenged 鱼类的活性增加，而在 48 和 72 h 时则检测不到。相比之下，在 challenged 后 48 和 72 h 时， challenged 鳗鲡的皮肤黏液中的蛋白酶活性降低。关于杀菌活性，在所有实验组的皮肤黏液中均观察到灿烂弧菌的高生长能力。有趣的是，与未 challenged 鱼类相比， challenged 鳗鲡的皮肤黏液在 48 h 时对该细菌表现出增强的杀菌活性。最后，在试验结束时（72 h）观察到鳃和肝脏出现严重的组织病理学改变，而 challenged 鱼类的皮肤仅表现出比未 challenged 鱼类更多的杯状细胞扩散存在。这些结果可能为这种原始物种的黏膜免疫系统提供新的见解，并可能在水产养殖中有潜在的应用。
