Arnizaut Ana B, Hanson Larry A
Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi 39762, USA.
Dis Aquat Organ. 2011 Jul 12;95(3):189-201. doi: 10.3354/dao02348.
Channel catfish virus (CCV, Ictalurid herpesvirus 1) and CCV disease have been extensively studied. Yet, little is known about CCV-host interaction after resolution of the primary infection. In order to determine potential recrudescence of CCV from latency, we established latency by exposing channel catfish juveniles with CCV or a thymidine kinase-negative recombinant (CCVlacZ) at a dose that caused less than 20% mortality. Then, we evaluated antibody response by serially sampling the same fish at 0 (pre-infection), 30, 60 and 90 d post challenge (DPC). We then attempted to induce viral recrudescence by intramuscular administration of dexamethasone and sampled the fish at 2, 4, 7, or 10 d post treatment. Recrudescence was evaluated by leukocyte co-cultivation and cell culture of tissue homogenates but no virus was detected. Western blot data demonstrated the highest number of seropositive fish by 30 DPC and a secondary antibody induction after dexamethasone treatment. The antigen specificity of the secondary response corresponded to viral proteins with molecular masses similar to those recognized by the same fish by 30 DPC. The recognized proteins were predominantly large, ranging from approximately 90 to >200 kDa. Expression analysis of selected virus genes at 90 DPC and following dexamethasone treatment demonstrated occasional immediate-early virus gene expression in peripheral blood leukocytes. Early and late gene expression was rarely detected. The combined data suggest restricted re-activation of CCV in our experimental system. Primary and secondary responses and virus gene expression were demonstrated in CCVlacZ-exposed fish but were less frequent than in CCV-exposed fish.
斑点叉尾鮰病毒（CCV，鮰疱疹病毒1型）和CCV病已得到广泛研究。然而，对于初次感染消退后CCV与宿主的相互作用却知之甚少。为了确定CCV从潜伏状态潜在的复发情况，我们通过用CCV或胸苷激酶阴性重组体（CCVlacZ）以导致死亡率低于20%的剂量感染斑点叉尾鮰幼鱼来建立潜伏状态。然后，我们在攻毒后0（感染前）、30、60和90天对同一条鱼进行连续采样，以评估抗体反应。随后，我们试图通过肌肉注射地塞米松诱导病毒复发，并在治疗后2、4、7或10天对鱼进行采样。通过白细胞共培养和组织匀浆的细胞培养来评估复发情况，但未检测到病毒。蛋白质印迹数据显示，到攻毒后30天血清阳性鱼数量最多，地塞米松治疗后出现二次抗体诱导。二次反应的抗原特异性与分子量类似于攻毒后30天同一条鱼所识别的病毒蛋白相对应。所识别的蛋白主要是大分子，范围从大约90 kDa到>200 kDa。在攻毒后90天以及地塞米松治疗后对选定病毒基因的表达分析表明，外周血白细胞中偶尔有立即早期病毒基因表达。很少检测到早期和晚期基因表达。综合数据表明，在我们的实验系统中CCV的重新激活受到限制。在暴露于CCVlacZ的鱼中也证实了初次和二次反应以及病毒基因表达，但比暴露于CCV的鱼中出现的频率要低。
