Studies of the ecology and pathogenicity of Newcastle disease virus.

对纽卡斯尔疫病毒（NDV）的生态学和致病性进行了研究。NDV的血凝素-神经氨酸酶（HN）和融合蛋白（F）在NDV感染过程中起重要作用。将HN和F基因分别插入到牛痘病毒、鸡痘病毒和杆状病毒中，检测其表达产物的生物学和免疫学特性。获得了以下结果：1）使用表达HN蛋白的重组痘苗病毒（rVV-HN）研究了针对HN蛋白的免疫应答在保护抵抗NDV感染中的作用。用Eve rVV-HN（8 × 10 ^<>6 PFU）接种的鸡完全免受强毒NDV的致死感染。用灭活的RVV-HN接种鸡不受保护。2）构建了表达HN蛋白的重组FPV（rFPV-HN），并在大肠杆菌中进行了表达。 ...更多信息 在FPV的胸苷激酶基因内控制VV启动子p7.5。HFPV-HN与抗HN单克隆抗体反应，具有中和病毒的活性。表达的HN蛋白在SDS-PAGE上具有与真实HN蛋白相同的迁移率。3）用含有NDV HN蛋白cDNA的重组BV（rBV-HN）感染草地贪夜蛾（Spodoptera frugiperda，Sf）细胞，在其表面表达HN蛋白。表达的HN蛋白在SDS-PAGE上具有与真实HN糖蛋白相同的迁移率，并且衣霉素处理降低了HN蛋白的表观摩尔数。重量表达的蛋白质的mol.重量4）构建了4株携带NDV强毒株和弱毒株F蛋白基因的重组BV，分别为完整型和缺失C端膜锚结构域的截短型，并对表达产物进行了分析。强毒株的F蛋白只有完整的F蛋白被蛋白水解为F_1和F_2亚基，F_1和F_2亚基通过二硫键结合在分子间。少

The purpose of the present study is to evaluate the ecology and pathogenicity of Newcastle disease virus (NDV). The hemagglutinin-neuraminidase (HN) and fusion (F) proteins of NDV were known to play key roles in the course of NDV infection. We examined biological and immunological properties of the expressed HN or F protein after inserting these genes into vaccinia virus (VN), fowlpox virus (FPV) or baculovius (BV). The following results were obtained.1) The role of immune responses to HN protein in protection against NDV infection was investigated using a recombinant vaccinia virus (rVV-HN) expressing the HN protein. Chickens inoculated with Eve rVV-HN(8x10^<>6 PFU) were completely protected from lethal infection with virulent NDV. Chickens inoculated with inactivated RVV-HN were not protected. Specific antibodies against the HN protein of NDV were detected in stra from survivors but not from dying birds.2) We constructed a recombinant FPV (rFPV-HN) expressing the HN protein under con … More trol of VV promoter p7.5 within thymidine kinase gene of FPV. The RFPV-HN reacted with ante-HN monoclonal antibody with virus neutralizing activity. The expressed HN protein had the same mobility on SDS-PAGE as the authentic HN glycoprotein.3) Spodoptera frugiperda (Sf) cells which infected with a recombinant BV (rBV-HN) containing a cDNA which encodes HN of NDV were expressed the antigen on their surface. The expressed HN protein had the same mobility on SDS-PAGE as the authentic HN glycoprotein, and tunicamycin treatment reduced the apparent mol. wt. of the expressed protein to the mol. wt. of unglycosylated HN protein which is calculated from the nucleotide sequence.4) Four recombinant BV carrying F protein genes of virulent and avirulent strains of NDV with two different forms, intact and truncate form which lacks a C-terminal membrane anchor domain, were constructed the expressed proteins were analyzed. Only intact form of the F protein of virulent strain was proteolytically cleaved into F_1 and F_2 subunits which were bound intermolecularly by disulfide bound. Less