鸭乙型肝炎病毒Ⅹ样开放读码框架及其表达蛋白

随着鸭乙型肝炎模型越来越广泛地应用于嗜肝病毒的生命周期、慢性乙型肝炎病毒感染的规律和抗病毒药物筛选等研究,鸭乙型肝炎病毒也得到了更深入的认识,尤其是在鸭乙型肝炎病毒的基因结构上.目前已经知道鸭乙型肝炎病毒在跟哺乳动物嗜肝DNA病毒X基因相似的区域存在X样开放读码框架,也可以表达一种跟X蛋白功能相近的X样蛋白.本文就X样开放读码框架和X样蛋白的发现过程,X样蛋白的组织学定位,以及X样蛋白功能的研究进展作一综述.     

广东省绿头鸭场鸭乙肝病毒自然携带状况调查

目的　调查两个鸭场携带乙肝病毒(DHBV)状况。方法　在对广东省家养绿头鸭分布状况进行系统调查的基础上,对南海市和顺镇、里水镇两个绿头鸭场作了随机抽样调查,采集了雏鸭、青年鸭和种鸭的血标本共519份,应用斑点分子杂交(DotBlot)测定法观察绿头鸭乙型肝炎病毒(DHBV)自然携带率。结果　两鸭场绿头鸭的DHBV自然携带率为36.0%(187/519),其95%可信限为31.0%～44.0%。不同鸭龄组绿头鸭DHBV自然携带比较,两鸭场同日龄绿头鸭DHBV自然携带率比较,绿头鸭DHBV自然携带率的性别比较,差异均无显著意义。不同鸭龄的绿头鸭DHBV-DNA含量定量分析(A值),差异有非常显著性(P＜0.01),其含量由高到低顺序为雏鸭＞种鸭＞青年鸭,和顺鸭场的绿头鸭DHBV-DNA含量高于里水鸭场。结论　两鸭场绿头鸭携带的DHBV可能源于不同的亚株。     

用嗜肝DNA病毒模型筛选抗病毒中草药

对叶下珠等21种中草药进行抗乙肝病毒药物研究,通过体外及体内逐步筛选发现,叶下珠和虎杖提取物对鸭乙型肝炎病毒(DHBV)及乙型肝炎病毒(HBV)均有较好的抑制效果,旱莲草对HBVDNAp有一定的抑制作用。     

复方药物ZL-1在鸭乙型肝炎病毒实验感染模型中抗病毒作用的研究

目的　研究中药复方ZL 1在鸭乙型肝炎病毒 (DHBV)持续性感染模型中抗嗜肝DNA病毒的作用。方法应用中药复方ZL 1治疗实验感染鸭 ,口服给药 ,剂量 5 0 0mg·kg-1·d-1,分 2次服用 ,连续 4周。采用斑点分子杂交和Southern印迹杂交检测治疗后感染鸭血清和肝脏中病毒的动态变化。同时以拉米夫定及安慰剂作为对照组。结果　复方药物ZL 1治疗后血清中DHBVDNA均数从 3 .6× 10 10 拷贝 /ml下降至 0 .9× 10 10 拷贝 /ml(P <0 .0 1) ,抑制病毒率为 75 % ,但尚不能清除病毒血症 ,肝组织中总DHBVDNA和DHBV超螺旋型DNA量无明显减少 ,停药观察 2周 ,病毒复制反弹不明显。拉米夫定治疗后可显著降低病毒血症 (P <0 .0 1) ,抑制病毒率达 99% ,同时肝组织中总DHBVDNA和DHBV超螺旋型DNA量减少 ,但停药观察 2周 ,病毒复制反弹明显。安慰剂组 (口服生理盐水 )治疗前后病毒水平的差异无显著性 (P >0 .0 5 )。结论　复方药物ZL 1治疗4周可使感染鸭病毒血症降低 ,但不能清除病毒血症 ,肝脏中病毒复制水平也无显著下降     

Mutations outside the YMDD motif in the P protein can also cause DHBV resistant to Lamivudine

AIM: To observe the Lamivudine resistance character of a DHBV strain in vitro and in vivo, and to analyze if the Lamivudine resistance character is caused by gene mutation or by abnormity of the Lamivudine metabolism. METHODS: Congenitally DHBV-negative Guangdong brown ducks and duck embryo liver cells were respectively taken as animal and cell model. The Lamivudine-susceptive DHBV and Lamivudine-resistant DHBV (LRDHBV) were infected and Lamivudine was administrated according to the divided groups. The changes of DHBV quantity in the animal and cell model were tested. Three Lamivudine-resistant and two Lamivudine-susceptive DHBV complete genomes were successfully amplified, sequenced and then submitted to GenBank. All the DHBV complete sequences in the GenBank at present were taken to align with the three LRDHBV to analyze the mutational points related to the Lamivudine-resistant mutation. RESULTS: Both the animal and cell model showed that the large and the small dosage Lamivudine have no significant inhibitory effect on the LRDHBV. Rve sequences of DHBV complete genomes were successfully cloned. The GenBank accession numbers of the three sequences of LRDHBV are AY521226, AY521227, and AY433937. The two strains of Lamivudine-susceptive DHBV are AY392760 and AY536371. The correlated mutational points are KorR86Q and AorE591T in the P protein. CONCLUSION: The Lamivudine resistance character of this DHBV strain is caused by genome mutation; the related mutational points are KorR86Q and AorE591T and have no relations with the YMDD motif mutation.     

鸭乙型肝炎动物模型的建立和DHBV在肝脏的定位研究

本文利用ＤＨＢＶ阳性血清感染１日龄雏鸭，感染后２、４、８周以血清斑点杂交和Ｄｏｔ－ＥＩＡ检测鸭血清中的ＤＨＢＶ－ＤＮＡ和ＤＨＢｓＡｇ，其阳性率分别为５６．３％、６５．６％、７４．２％和５３．１％、７１．９％、７０．９％。进一步采用原位杂交和免疫组化对鸭肝组织内ＤＨＢＶ－ＤＮＡ和ＤＨＢｓＡｇ进行检测，结果表明ＤＨＢＶ－ＤＮＡ主要存在于细胞浆中，而ＤＨＢｓＡｇ主要分布于细胞浆及细胞膜。对肝组织的病理检查及胶原纤维特殊检测发现，ＤＨＢＶ阳性组与阴性组无明显差别。     

IFN-γ increases efficiency of DNA vaccine in protecting ducks against infection

AIM: To detect the effects of DNA vaccines in combination with duck IFN-gamma gene on the protection of ducks against duck hepatitis B virus (DHBV) infection. METHODS: DuIFN-gamma cDNA was cloned and expressed in COS-7 cells, and the antiviral activity of DuIFN-gamma was detected and neutralized by specific antibodies. Ducks were vaccinated with DHBpreS/S DNA alone or co-immunized with plasmid expressing DuIFN-gamma. DuIFN-gamma mRNA in peripheral blood mononuclear cells (PBMCs) from immunized ducks was detected by semi-quantitative competitive RT-PCR. Anti-DHBpreS was titrated by enzyme-linked immunosorbent assay (ELISA). DHBV DNA in sera and liver was detected by Southern blot hybridization, after ducks were challenged with high doses of DHBV. RESULTS: DuIFN-gamma expressed by COS-7 was able to protect duck fibroblasts against vesicular stomatitis virus (VSV) infection in a dose-dependent fashion, and anti-DuIFN-gamma antibodies neutralized the antiviral effects. DuIFN-gamma in the supernatant also inhibited the release of DHBV DNA from LMH-D2 cells. When ducks were co-immunized with DNA vaccine expressing DHBpreS/S and DuIFN-gamma gene as an adjuvant, the level of DuIFN-gamma mRNA in PBMCs was higher than that in ducks vaccinated with DHBpreS/S DNA alone. However, the titer of anti-DHBpreS elicited by DHBpreS/S DNA alone was higher than that co-immunized with DuIFN-gamma gene and DHBpreS/S DNA. After being challenged with DHBV at high doses, the load of DHBV in sera dropped faster, and the amount of total DNA and cccDNA in the liver decreased more significantly in the group of ducks co-immunized with DuIFN-gamma gene and DHBpreS/S DNA than in other groups. CONCLUSION: DHBV preS/S DNA vaccine can protect ducks against DHBV infection, DuIFN-gamma gene as an immune adjuvant enhances its efficacy.     

鸭乙型肝炎病毒聚合酶结合模拟肽真核表达载体的构建

目的：构建与鸭乙型肝炎病毒聚合酶(DHBV P)特异性结合的模拟肽的重组真核表达质粒，为进一步将重组质粒转染原代培养鸭肝细胞研究模拟肽的作用奠定基础。方法：以噬菌体肽库中筛选出来的能特异性结合DHBV P的模拟肽基因为模板，扩增模拟肽基因片段，并应用基因重组技术构建其真核表达载体pEGFP-N1-模拟肽基因(pEGFP-N1-M)。结果：经鉴定，目的基因片段以正确的方向插入载体pEGFP-N1中，序列正确，对码正确。结论：成功构建了重组真核表达质粒pEGFP-N1-M。     

短波紫外线与交联淀粉碘联用对血浆中鸭乙型肝炎病毒灭活的研究

采用３Ｈ渗入检测法、免疫电镜、ＥＬＩＳＡ法、雏鸭感染试验等技术,观察短波紫外线（ＵＶＣ）与交联淀粉碘（ＣＳＩ）联用对血浆中鸭乙型肝炎病毒（ＤＨＢＶ）的灭活效果。结果,在７１７０Ｊ／ｍ２ＵＶＣ照射后,再经 ＣＳＩ １００ ｍｇ／ ｍｌ作用 ９０ ｍｉｎ,血浆中 ＤＨＢＶ ＤＮＡ—Ｐ活性下降 ９９．７６％, ＤＨＢＶ颗粒破坏,而 ＤＨＢｓＡｇ为阳性,雏鸭感染比率为 ２／ １３。若 ＣＳＩ作用时间延长至 １２０ ｍｉｎ,血浆中 ＤＨＢｓＡｇ滴度进一步下降但仍呈阳性,雏鸭感染比率却为０／ １０。     

Enhanced magnitude and breadth of neutralizing humoral response to a DNA vaccine targeting the DHBV envelope protein delivered by in vivo electroporation

We explored in the duck hepatitis B virus (DHBV) model the impact of electroporation (EP)-mediated DNA vaccine delivery on the neutralizing humoral response to viral preS/S large envelope protein. EP enhanced the kinetics and magnitude of anti-preS response compared to the standard needle DNA injection (SI). Importantly, EP dramatically enhanced the neutralizing potency of the humoral response, since antibodies induced by low DNA dose (10 μg) were able to highly neutralize DHBV and to recognize ten antigenic regions, including four neutralization epitopes. Whereas, SI-induced antibodies by the same low DNA dose were not neutralizing and the epitope pattern was extremely narrow, since it was limited to only one epitope. Thus, EP-based delivery was able to improve the dose efficiency of DNA vaccine and to maintain a highly neutralizing, multi-specific B-cell response, suggesting that it may be an effective approach for chronic hepatitis B therapy at clinically feasible DNA dose.