Department of Life Sciences and Biotechnology, University of Ferrara, St. Borsari 46, 44121, Ferrara, Italy.
Department of Cellular and Environmental Biology, University of Perugia, St. Elce di sotto 5, 06123, Perugia, Italy.
Parasit Vectors. 2018 Jul 16;11(1):424. doi: 10.1186/s13071-018-3002-6.
The Northern pike, Esox lucius, is a large, long-lived, top-predator fish species and occupies a broad range of aquatic environments. This species is on its way to becoming an important model organism and has the potential to contribute new knowledge and a better understanding of ecology and evolutionary biology. Very few studies have been done on the intestinal pathology of pike infected with helminths. The present study details the first Italian record of adult Acanthocephalus lucii reported in the intestine of E. lucius.
A total of 22 pike from Lake Piediluco (Central Italy) were examined, of which 16 (72.7%) were infected with A. lucii. The most affected areas of gastrointestinal tract were the medium and distal intestine. The intensity of infection ranged from 1 to 18 parasites per host. Acanthocephalus lucii penetrated mucosal and submucosal layers which had a high number of mast cells (MCs) with an intense degranulation. The cellular elements involved in the immune response within the intestine of pike were assessed by ultrastructural techniques and immunohistochemistry using antibodies against met-enkephalin, immunoglobulin E (IgE)-like receptor (FCεRIγ), histamine, interleukin-6, interleukin-1β, substance P, lysozyme, serotonin, inducible-nitric oxide synthase (i-NOS), tumor necrosis factor-α (TNF-α) and the antimicrobial peptide piscidin 3 (P3). In intestines of the pike, several MCs were immunopositive to 9 out of the 11 aforementioned antibodies and infected fish had a higher number of positive MCs when compared to uninfected fish.
Pike intestinal tissue response to A. lucii was documented. Numerous MCs were seen throughout the mucosa and submucosal layers. In infected and uninfected intestines of pike, MCs were the dominant immune cell type encountered; they are the most common granulocyte type involved in several fish-helminth systems. Immunopositivity of MCs to 9 out of 11 antibodies is of great interest and these cells could play an important key role in the host response to an enteric helminth. This is the first report of A. lucii in an Italian population of E. lucius and the first account on positivity of MCs to piscidin 3 and histamine in a non-perciform fish.
北梭鱼，Esox lucius，是一种大型、长寿、顶级掠食性鱼类，分布于广泛的水生环境中。该物种正逐渐成为一种重要的模式生物，有望为生态学和进化生物学提供新知识和更深入的理解。很少有研究涉及感染寄生虫的梭鱼的肠道病理学。本研究详细介绍了在 E. lucius 肠道中首次报道的成年 Acanthocephalus lucii 在意大利的记录。
总共检查了来自意大利 Piediluco 湖（意大利中部）的 22 条梭鱼，其中 16 条（72.7%）感染了 A. lucii。胃肠道受影响最严重的区域是中肠和远肠。感染强度范围为每个宿主 1 到 18 个寄生虫。Acanthocephalus lucii 穿透了具有大量肥大细胞（MCs）的粘膜和粘膜下层，这些细胞有强烈的脱颗粒现象。通过超微结构技术和针对 met-enkephalin、免疫球蛋白 E（IgE）样受体（FCεRIγ）、组织胺、白细胞介素-6、白细胞介素-1β、物质 P、溶菌酶、血清素、诱导型一氧化氮合酶（i-NOS）、肿瘤坏死因子-α（TNF-α）和抗菌肽 Piscidin 3（P3）的免疫组化技术评估了梭鱼肠道中参与免疫反应的细胞成分。在梭鱼的肠道中，有 9 种抗体中的 11 种抗体对多种 MC 呈免疫阳性，并且与未感染的鱼类相比，感染鱼类的 MC 数量更多。
记录了梭鱼肠道组织对 A. lucii 的反应。在整个粘膜和粘膜下层都可以看到大量的 MC。在感染和未感染的梭鱼肠道中，MC 是遇到的主要免疫细胞类型；它们是参与多种鱼类-寄生虫系统的最常见的粒细胞类型。MC 对 9 种抗体中的 11 种抗体呈免疫阳性，这非常有趣，这些细胞可能在宿主对肠道寄生虫的反应中发挥重要作用。这是 A. lucii 在意大利 E. lucius 种群中的首次报道，也是 MC 对非鲈形目鱼类的 Piscidin 3 和组织胺呈阳性的首次报道。
