The promolion of membrzme fusion by the fusion (F) protein of human parathfluenza vires 3 (fiPIV3) is dependenl on a vies specific eontnbution from the fiemagglulinin-neuraminidase (HN) protein By evaluarion of chimeric hPIV3-Newcasfle disease vires (NDV) HN proteins, we have previously show n that hPl V3 F-speci ficity is determined by a domain that extends lYnm the middle of the membrane anchor to the 82rid residue in the ectodomain [Virology 209. (1995) 457; Arch Virol 13 (1997) 115]. If the corresponding NDV-derived residues replace the two C-terminat residues in this domain, no fusion is dcteeled. However. these substitutions restore a glycosyladon sile present in NDV HN, but not in hPIV3 HN. Deletion of this site from a nested set of chbneras with fiPIV3-derived N terminal porlions of decreasing length partially restores fusion, suggesting that an ofigosacchande near the top of hPIV3 HN stalk modulates fusion In addition, further mutational analyses show that a chimera with only 125 N temdnal hPIV3-dedved residues (72 in the stalk) actually promotes fusion more efficiently than Ihe wt protein These findings Iocalize the C ternrinus of the F-specific domain in hPlV3 HN n full 10 residues closer to the membrane than previously shown

Objective: To investigate the correlagon between rubella Jrus (RuV) antigen in peripheral Jymphocytes, the im mLine status and RuV infection in the central nervous system (CNS). Metbods: BALB/c mice were used as a model and treated with immunoaffecting medicines. Then, the mice were infected with RuV via the abdominal cavity, and the antigen lever in peripheral lymphocytes was examined 1.3, 7 and 14 days postinfection. RuV in the CNS was detected by immunohistocbemical meth ods. BALB/c mice were given dexamethasone and cytoxan before infection with the RuV JR23 strain. Immune functions and RuV invasion of the CNS were assayed on day 21 postinfection via the abdominal cavity, and their relationship was analyzed. Results: The mean antigen

The ectodomain of the paramyxovirus haemagglutinin neuraminidase (HN) glycoprotein spike can be divided into two regions: a membrane-proximalp stalk-like structure and a terminal globular domain. The latter contains all the antibody recognition sites of the protein, as well as its receptor recognition and neuraminidase (NA) active sites. These two activities of the protein can be separated by monoclonal antibody functional inhibition studies and mutations in the 91obular domain. Herein, we show that mutation of several conserved residues in the stalk of the Newcastle disease virus HN protein markedly decrease its NA activity without a significant effect on receptor recognition. Thus, mutations in the stalk, distant from the NA active site in the globular domain, can also separate attachment and NA. These results add to an increasin9 body of evidence that the NA activity of this protein is dependent on an intact stalk structure.

To construct an expression vector containing the E1 glycoprotein gene of rubella virus for the study on the effect of mutation of the E1 gene glyeoprotein and the analysis of phylogenetic differences of sequences,the gene encoding the E1 envelope glcoprotein was amlified from rubella virus, Jinan strain JR23, by RT-PCR and ligated into PMD-18T vector. The clones that camied the E1 gene were identified after amp selection and analysis of restrition enzyme digenstion. After sequencing this gene was analyzed by Danstar and Winstar prograns, and the map of phyolgenetic tree was dramw. The colone of E1 glycoprotein was thus constructed. It was found that the sequence differeces between JR23 strain and the TCRB strain from Japan and those between JR23 strain and Thomas strain of England were rather small with difference values of 0.9% and 1.2% respectively. Yet those between JR23 strain and BRD2 strain from Beijing and those between JR23 strain and XC379 strain from Hong Kong were comperatively larger with difference values of 7.6% and 7.3% resoectivesly. The sequece of JR23 strain with other strains was less than 3% except the NC strain (3.7%). It concludes that the construction of E1 glcoprotein gene offers an approach to study the relationship between structures and functions of E1 gene and its gene products. In the phlogenetic tree, it shows that there are significant differences in the sequences of rebella vinus isolated in China, and this might be helpful to develop an effective vaccine.

目的 找到副牯病毒融合蛋白（F）分子上与血凝素-神经氪酸酶（HN）相互作用的特异性区域，弄清F融合细胞的分子机理。方法 采用基因定点突变法，创造一个酶切位点，得副突变株，然后用基因重组的方法得到各种重组株。并于真棱细胞内进行表达。Gimsa染色和指示基因法检测细胞融合功能，荧光强度分析（FACS）检测表达效率情况。结果 在将各有关F基因片段进行交换之前，创造一个酶切位点时所得突变株的细胞融合功能与野毒株相同；将新城疰病毒（NDV）F和副流感病毒（PIV）F在膜穿人部分和躯干部分交接处交换时。不影响细胞融合功能；进一步将F2进行交换时，也不影响细胞融台功能；而将F的头部进行交换时。则检测不到细胞融合作用，FACS分析表明，F没有达到细胞表面，结论 F分子上与HN相互作用的特异性区域位于膜穿大部分和躯干部分交接处与F1和F2交接处之间，即F1除去膜穿人部分和足部的剩余部分。