Centre for Environment, Fisheries and Aquaculture Science Weymouth Laboratory, Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, UK.
Centre for Environment, Fisheries and Aquaculture Science Weymouth Laboratory, Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, UK.
Fish Shellfish Immunol. 2018 Jul;78:355-363. doi: 10.1016/j.fsi.2018.04.053. Epub 2018 Apr 27.
Puffy skin disease (PSD) is an emerging skin condition which affects rainbow trout, Oncorhynchus mykiss (Walbaum). The transmission pattern of PSD suggests an infectious aetiology, however, the actual causative infectious agent(s) remain(s) unknown. In the present study, the rainbow trout epidermal immune response to PSD was characterised. Skin samples from infected fish were analysed and classified as mild, moderate or severe PSD by gross pathology and histological assessment. The level of expression of 26 immune-associated genes including cytokines, immunoglobulins and cell markers were examined by TaqMan qPCR assays. A significant up-regulation of the gene expression of C3, lysozyme, IL-1β and T-bet and down-regulation of TGFβ and TLR3 was observed in PSD fish compared to control fish. MHCI gene expression was up-regulated only in severe PSD lesions. Histological examinations of the epidermis showed a significant increase in the number of eosinophil cells and dendritic melanocytes in PSD fish. In severe lesions, mild diffuse lymphocyte infiltration was observed. IgT and CD8 positive cells were detected locally in the skin of PSD fish by in situ hybridisation (ISH), however, the gene expression of those genes was not different from control fish. Total IgM in serum of diseased animals was not different from control fish, measured by a sandwich ELISA, nor was significant up regulation of IgM gene expression in PSD lesions observed. Taken together, these results show activation of the complement pathway, up-regulation of a Th17 type response and eosinophilia during PSD. This is typical of a response to extracellular pathogens (i.e. bacteria and parasites) and allergens, commonly associated with acute dermatitis.
肿皮病（PSD）是一种新兴的皮肤疾病，影响虹鳟鱼（Oncorhynchus mykiss）。PSD 的传播模式表明其具有传染性病因，但实际的致病病原体仍不清楚。本研究对 PSD 虹鳟鱼的表皮免疫反应进行了研究。通过大体病理学和组织学评估，对感染鱼的皮肤样本进行分析和分类为轻度、中度或重度 PSD。采用 TaqMan qPCR 检测 26 种免疫相关基因（包括细胞因子、免疫球蛋白和细胞标记物）的表达水平。与对照鱼相比，PSD 鱼中 C3、溶菌酶、IL-1β 和 T-bet 的基因表达显著上调，而 TGFβ 和 TLR3 的基因表达下调。MHCI 基因表达仅在严重 PSD 病变中上调。表皮组织学检查显示，PSD 鱼中嗜酸性粒细胞和树突状黑素细胞的数量显著增加。在严重病变中，观察到轻度弥漫性淋巴细胞浸润。通过原位杂交（ISH）在 PSD 鱼的皮肤中局部检测到 IgT 和 CD8 阳性细胞，但这些基因的表达与对照鱼没有差异。通过夹心 ELISA 测量，患病动物血清中的总 IgM 与对照鱼没有差异，也没有观察到 PSD 病变中 IgM 基因表达的显著上调。综上所述，这些结果表明在 PSD 期间补体途径的激活、Th17 型反应的上调和嗜酸性粒细胞增多。这是对细胞外病原体（即细菌和寄生虫）和过敏原的典型反应，通常与急性皮炎有关。
