Department of Biology and Evolution, University of Ferrara, St. Borsari 46, 44123 Ferrara, Italy.
Dev Comp Immunol. 2012 Jan;36(1):174-82. doi: 10.1016/j.dci.2011.06.017. Epub 2011 Jul 5.
Light, ultrastructural and immunocytochemical investigations were carried out on the skin of gilthead seabream, Sparus aurata L., naturally infected with lymphocystis iridovirus, to assess pathology and host cellular responses. Of 220,000 young seabream examined, 32,400 (14.7%) had clinical signs of lymphocystis and within 6 months of disease appearance, 45% of clinically affected fish had died. A subsample of 20 S. aurata (80.0 ± 12.5mm total length, mean ± S.D.), including 10 with lymphocystis on the skin and 10 clinically normal, were examined via immunohistochemistry. Affected skin displayed macroscopic, wart-like clusters of hypertrophic fibroblasts which arose from the dermis and were covered by the epithelium. Clusters were encountered on the head, trunk and fins, but there was no evidence of visceral lymphocystis. The lymphocysts were surrounded by numerous granular cells that were positive for the antimicrobial peptide (AMP) piscidin 3 and underwent intense degranulation. To identify the type of granular cells involved in this viral disease, a double immunohistochemical staining with the monoclonal antibody G7 (mAb G7), which is specific for seabream acidophilic granulocytes (AGs), and with anti-histamine (as a marker for mast cells, MCs) was applied to the skin sections of the 10 clinically normal fish and 10 fish with lymphocystis. In infected skin, the number of G7-positive cells (i.e., AGs) (18.5 ± 10.5, mean number of cells per 20,000 μm(2) ± S.D.) was significantly higher compared to their density in uninfected skin (1.4 ± 2.2) (t test, p<0.01). Notably, the AGs that infiltrated the skin lesions of infected animals were found to be degranulated and to produce the pro-inflammatory cytokine interleukin-1β. No histamine-positive granular cells (i.e., MCs) were encountered in the lymphocystis lesions. The present study shows the response of skin to lymphocystis disease virus (LCDV) and provides evidence that AGs, but not MCs, are recruited and activated in response to this skin infection.
对自然感染淋巴囊肿病毒的真鲷皮肤进行了光镜、超微结构和免疫细胞化学研究，以评估病理学和宿主细胞反应。在检查的 22 万条幼鱼中，有 32400 条（14.7%）出现淋巴囊肿临床症状，在疾病出现后 6 个月内，45%的临床受影响鱼类死亡。从 20 条真鲷（全长 80.0 ± 12.5mm，平均值 ± S.D.）中抽取了一个亚样本，包括 10 条皮肤有淋巴囊肿和 10 条临床正常的真鲷，通过免疫组织化学进行了检查。受影响的皮肤显示出宏观的、疣状的、增生的成纤维细胞簇，这些细胞起源于真皮并被上皮覆盖。集群出现在头部、躯干和鳍上，但没有内脏淋巴囊肿的证据。淋巴囊肿周围有大量阳性的抗菌肽（AMP）鱼精蛋白 3 的颗粒细胞，并经历强烈的脱颗粒。为了鉴定参与这种病毒性疾病的颗粒细胞类型，对 10 条临床正常鱼和 10 条淋巴囊肿鱼的皮肤切片进行了单克隆抗体 G7（mAb G7）与抗组胺（作为肥大细胞 MC 的标志物）的双重免疫组织化学染色。在感染的皮肤中，G7 阳性细胞（即酸性粒细胞 AGs）的数量（18.5 ± 10.5，每 20000μm² ± S.D.的平均细胞数）与未感染皮肤的密度（1.4 ± 2.2）相比显著增加（t 检验，p<0.01）。值得注意的是，在感染动物的皮肤病变中浸润的 AGs被发现脱颗粒，并产生促炎细胞因子白细胞介素-1β。在淋巴囊肿病变中未发现组胺阳性的颗粒细胞（即 MCs）。本研究显示了皮肤对淋巴囊肿病病毒（LCDV）的反应，并提供了证据表明，AGs 而不是 MCs，在这种皮肤感染中被募集和激活。
