AboElkhair M, Synard S, Siah A, Pariseau J, Davidson J, Johnson G, Greenwood S J, Casey J W, Berthe F C J, Cepica A
Department of Pathology and Microbiology, Atlantic Veterinary College, Charlottetown, PE, Canada C1A 4P3.
J Invertebr Pathol. 2009 Oct;102(2):133-40. doi: 10.1016/j.jip.2009.06.009. Epub 2009 Jul 24.
Since all retroviruses possess reverse transcriptase (RT) enzyme, reverse transcriptase activity has been the main supportive evidence of retroviral etiology of haemic neoplasia (HN) in soft shell clams, Mya arenaria. The objective of the present study was to search for a putative retrovirus in various tissues of diseased clams following quantification of RT activity (biochemical indicator of retroviral infection). The clams were assessed by flow cytometry (FCM) for diagnosis of HN. RT activity was quantified by TaqMan-product enhanced reverse transcriptase (TM-PERT) assay in four different organs, gonad, gills, digestive gland, and mantle, at various stages of HN. The digestive gland, the organ with the highest RT activity, and haemocytes, the target cell of HN, were assessed by EM for presence of retroviruses. All organs were assessed by histology. The results of this study demonstrated that although all organs of healthy clams have some background RT activity, the activity observed in most of organs of diseased clams was significantly increased (p<0.05). An association was observed between the degree of neoplastic cell infiltration and the level of RT activity. Digestive gland showed the highest and most consistent RT activity in both healthy and diseased clams. No evidence for the existence of a retrovirus like particle was found by positive staining EM. The presence of RT activity without indications of retroviral particles in digestive gland and haemocytes suggests a probable endogenous source of RT.
由于所有逆转录病毒都拥有逆转录酶（RT），逆转录酶活性一直是软壳蛤（Mya arenaria）血液肿瘤（HN）逆转录病毒病因的主要支持证据。本研究的目的是在对逆转录酶活性（逆转录病毒感染的生化指标）进行定量后，在患病蛤的各种组织中寻找一种假定的逆转录病毒。通过流式细胞术（FCM）对蛤进行评估以诊断HN。在HN的各个阶段，通过TaqMan产物增强逆转录酶（TM-PERT）测定法对性腺、鳃、消化腺和外套膜这四个不同器官中的逆转录酶活性进行定量。对消化腺（逆转录酶活性最高的器官）和血细胞（HN的靶细胞）进行电子显微镜检查以确定是否存在逆转录病毒。对所有器官进行组织学评估。本研究结果表明，虽然健康蛤的所有器官都有一些背景逆转录酶活性，但在患病蛤的大多数器官中观察到的活性显著增加（p<0.05）。观察到肿瘤细胞浸润程度与逆转录酶活性水平之间存在关联。消化腺在健康和患病蛤中均显示出最高且最一致的逆转录酶活性。通过阳性染色电子显微镜未发现类似逆转录病毒颗粒存在的证据。消化腺和血细胞中存在逆转录酶活性但无逆转录病毒颗粒迹象，这表明逆转录酶可能来源于内源性。
