Modification of infection pattern of Duck hepatitis B virus by immuno regulatory durgs in both carrier and non-carrier ducks

为探讨鸭乙肝病毒感染时间、感染方式和水平疾病之间的关系，进行了鸭乙肝病毒的实验传播。雏鸭1日龄和3日龄接种DHBV后出现持续感染，5日龄后接种雏鸭出现一过性病毒血症。雏鸭接种DHBV后第3天及以后出现肝炎活动，与乙肝病毒相关性肝病相比，肝炎活动度很低。其次，探讨了免疫调节药物对DHBV感染模式的影响。环磷酰胺免疫抑制治疗延长了病毒期，几乎没有肝脏炎症。激素治疗没有抑制肝炎，而且增加了病毒复制和延长了病毒期。OK-432免疫模拟治疗显示肝脏炎症增加，但不增加病毒复制。这些药物对D乙肝病毒感染模式的改变与对乙肝病毒感染模式的改变非常相似。宿主免疫反应似乎在确定感染模式和肝脏炎症活动性方面有相当大的作用。这些结果表明，DHBV可以作为研究病毒性肝炎宿主-病毒相互作用和免疫机制的一种有用的病毒模型。

To investigate the relationship among the time of viral infection, infection pattern and lever diseases experimental transmission of Duck hepatitis B virus (DHBV) was performed. Inoculation of DHBV into ducks on 1 day and 3 day posthatch revealed persistent infection, whereras inoculation into those on and after 5 day posthatch showed transient viremia. Hepatitis activity was seen in ducks inoculated with DHBV on and after 3 day posthatch and was very weak compared with HBV associated liver diseases. Second, alteration of infection pattern of DHBV by immuno regulatory drugs was investigated. Immunosuprresive treatment with cyclophosphamide extended viremic period and showed almost no hepatic inflammation. Treatment of steroid did not suppress the hepatitis and moreover increased viral replication and extended viremic period. Immuno stimmulation treatment with OK-432 showed increase in hepatic inflammation but did not increase viral replication. Alterations of infection pattern of DHBV with these drugs were quite similar to that of HBV. Host immune response seems to have a considerable role on determination of infection pattern and activity of hepatic inflammation. With these results DHBV can be a helpful model of HBV for studying host-viral interaction and immunological mechanism of viral hepatitis.