Korbut Rozalia, Mehrdana Foojan, Kania Per Walter, Larsen Marianne Halberg, Frees Dorte, Dalsgaard Inger, Jørgensen Louise von Gersdorff
Laboratory of Aquatic Pathobiology, Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
Food Safety and Zoonoses, Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
PLoS One. 2016 Jul 12;11(7):e0158968. doi: 10.1371/journal.pone.0158968. eCollection 2016.
Immersion-vaccines (bacterins) are routinely used for aquacultured rainbow trout to protect against Yersinia ruckeri (Yr). During immersion vaccination, rainbow trout take up and process the antigens, which induce protection. The zebrafish was used as a model organism to study uptake mechanisms and subsequent antigen transport in fish. A genetically modified Yr was developed to constitutively express green fluorescent protein (GFP) and was used for bacterin production. Larval, juvenile and adult transparent zebrafish (tra:nac mutant) received a bath in the bacterin for up to 30 minutes. Samples were taken after 1 min, 15 min, 30 min, 2 h, 12 h and 24 h. At each sampling point fish were used for live imaging of the uptake using a fluorescence stereomicroscope and for immunohistochemistry (IHC). In adult fish, the bacterin could be traced within 30 min in scale pockets, skin, oesophagus, intestine and fins. Within two hours post bath (pb) Yr-antigens were visible in the spleen and at 24 h in liver and kidney. Bacteria were associated with the gills, but uptake at this location was limited. Antigens were rarely detected in the blood and never in the nares. In juvenile fish uptake of the bacterin was seen in the intestine 30 min pb and in the nares 2 hpb but never in scale pockets. Antigens were detected in the spleen 12 hpb. Zebrafish larvae exhibited major Yr uptake only in the mid-intestine enterocytes 24 hpb. The different life stages of zebrafish varied with regard to uptake locations, however the gut was consistently a major uptake site. Zebrafish and rainbow trout tend to have similar uptake mechanisms following immersion or bath vaccination, which points towards zebrafish as a suitable model organism for this aquacultured species.
浸泡疫苗（菌苗）常用于水产养殖的虹鳟鱼，以预防鲁氏耶尔森菌（Yr）感染。在浸泡疫苗接种过程中，虹鳟鱼摄取并处理抗原，从而产生保护作用。斑马鱼被用作模式生物，以研究鱼类的摄取机制和随后的抗原转运。构建了一种经过基因改造的Yr，使其组成性表达绿色荧光蛋白（GFP），并用于生产菌苗。将幼体、幼鱼和成体透明斑马鱼（tra:nac突变体）在菌苗中浸泡长达30分钟。在1分钟、15分钟、30分钟、2小时、12小时和24小时后采集样本。在每个采样点，使用荧光体视显微镜对鱼进行摄取的活体成像，并进行免疫组织化学（IHC）检测。在成鱼中，30分钟内可在鳞片袋、皮肤、食道、肠道和鳍中追踪到菌苗。浸泡后两小时（pb），脾脏中可见Yr抗原，24小时后在肝脏和肾脏中可见。细菌与鳃相关，但在该部位的摄取有限。血液中很少检测到抗原，鼻孔中从未检测到。在幼鱼中，浸泡后30分钟在肠道中可见菌苗摄取，2小时pb在鼻孔中可见，但鳞片袋中从未见。浸泡后12小时在脾脏中检测到抗原。斑马鱼幼体仅在浸泡后24小时在中肠肠细胞中表现出主要的Yr摄取。斑马鱼的不同生命阶段在摄取部位方面存在差异，但肠道始终是主要的摄取部位。斑马鱼和虹鳟鱼在浸泡或浴式疫苗接种后的摄取机制往往相似，这表明斑马鱼是这种水产养殖物种的合适模式生物。
