Studies of the ecology and pathogenicity of Newcastle disease virus.

本研究的目的是评价新城疫病毒（NDV）的生态学和致病性。已知NDV的血凝素-神经氨酸酶（HN）和融合(F)蛋白在NDV感染过程中起关键作用。在牛痘病毒（VN）、鸡痘病毒（FPV）和杆状病毒（BV）中插入表达的HN或F蛋白后，我们检测了这些基因的生物学和免疫学特性。得到了以下结果：1)利用表达HN蛋白的重组痘苗病毒（rVV-HN）研究了HN蛋白免疫应答对NDV感染的保护作用。接种了Eve rVV-HN（8x10^<>6 PFU）的鸡完全不受NDV致死性感染。用灭活的RVV-HN接种的鸡不受保护。在幸存者的stra中检测到针对NDV HN蛋白的特异性抗体，而在死亡的禽类中未检测到。2)构建了在胸苷激酶基因VV启动子p7.5调控下表达HN蛋白的重组FPV （rFPV-HN）。RFPV-HN与具有病毒中和活性的抗hn单克隆抗体反应。表达的HN蛋白在SDS-PAGE上具有与原HN糖蛋白相同的迁移率。3)将含有NDV HN基因cDNA的重组BV （rBV-HN）感染后的frugiperda Spodoptera （Sf）细胞表面表达该抗原。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，tunicamycin处理使表达蛋白的表观分子量降低到从核苷酸序列计算的未糖基化HN蛋白的分子量。4)构建了4个携带完整型和缺失c端膜锚定结构域的截断型NDV毒株和无毒株F蛋白基因的重组BV，并对表达蛋白进行了分析。毒株中只有完整的F蛋白被蛋白水解裂解为F_1和F_2亚基，并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