Aeromonas hydrophila (A. hydrophila) is a gram-negative opportunistic pathogen widely distributed in the aquatic environment, which can infect humans, birds, amphibians, reptiles, and fishes. However, the interaction between A. hydrophila and host cells has not been well characterized. In the present study, we investigated the role of autophagy in grass carp (Ctenopharyngodon idella) monocytes/macrophages following infection with A. hydrophila. Our results found that A. hydrophila challenge significantly induced autophagy, as shown by the increase of microtubule-associated protein 1 light chain 3 Ⅱ (LC3 Ⅱ) proteins and LC3 puncta in the cells. Moreover, by using confocal microscopy, the A. hydrophila-elicited autophagy was further confirmed by the colocalization of the A. hydrophila with LC3-positive autophagosome in the cells. In return, the effect of the activated autophagy on the survival of A. hydrophila was examined in the same cell model, showing that rapamycin-induced autophagy was effective in restricting the survival of A. hydrophila. In contrast, autophagy blocked by 3-methyladenine (3-MA) enhanced the amount of A. hydrophila in the cells. All these findings for the first time revealed the role of autophagy in the process of A. hydrophila invading fish immune cells.

嗜水气单胞菌（A. hydrophila）是一种革兰氏阴性机会病原体，广泛分布于水生环境中，可感染人类，鸟类，两栖动物，爬行动物和鱼类。但是，亲水链球菌与宿主细胞之间的相互作用尚未得到很好的表征。在本研究中，我们调查（自体吞噬在草鱼的作用草鱼）的单核/感染后巨噬细胞嗜水气单。我们的研究结果发现嗜水链球菌攻击显着诱导自噬，如细胞中微管相关蛋白1轻链3Ⅱ（LC3Ⅱ）蛋白和LC3点状蛋白的增加所表明。此外，通过共聚焦显微镜，亲水曲霉引起的自噬进一步通过亲水曲霉与LC3阳性自噬体在细胞中的共定位而得到证实。作为回报，对生存的活化自体吞噬的效果嗜水在相同的细胞模型进行了检查，显示出雷帕霉素诱导自噬是有效地限制的存活嗜水。与此相反，自噬阻挡增强量3-甲基腺嘌呤（3-MA）嗜水在细胞中。所有这些发现首次揭示了自噬在嗜水链球菌入侵鱼类免疫细胞过程中的作用。