Genetic Analysis and molecur Epidemiology of Parainfluenza virus type 4

克隆了人副流感病毒4B型（hPIV-4B）血凝素-神经氨酸酶（HN）蛋白的cdna，并测定了其核苷酸序列。hPIV -4A蛋白与4B - HN蛋白的核苷酸序列具有较高的同源性（81.4%），推导出的氨基酸序列具有87.3%的同源性。这种同一性程度被认为大于hPIV -4A和-4B HN蛋白之间使用单克隆抗体测定的免疫学相似性。为了阐明hPIV-4A和-4B HN蛋白抗原差异的原因，我们构建了3个潜在n -糖基化位点与hPIV-4A HN cDNA部分或完全相同的hPIV -4B HN cDNA。我们比较了表达的野生型和突变型蛋白的抗原性，发现突变型hPIV -4B HN蛋白的抗原性比非突变型hPIN -4B HN蛋白更接近hPIV -4A HN蛋白。该研究表明，hPIV -4A和-4B之间的抗原差异部分是由糖基化位点的缺失或产生引起的，这表明点突变导致糖基化位点的缺失或产生是导致病毒分裂为亚型的最初步骤之一。研究了人副流感病毒4A型（hPIV -4A）和4B型（hPIV -4B）在猴肾LLC-MK2细胞系（MK2细胞）和小鼠L929细胞系（L929细胞）中的复制能力。MK2细胞和L929细胞系（L929细胞）。MK2细胞和L929细胞都不允许hPIV -4复制。乙酰化胰蛋白酶对MK2细胞的病毒复制有效，但对L929细胞的病毒复制效果较差。内源性产生的干扰素（IFN）在L929细胞的复制中不起作用。L929细胞抑制病毒特异性多肽的合成，未检测到HN -mTNA。这些结果表明，hPIV -4可以同时感染MK2细胞和L929细胞。在MK2细胞中，当蛋白酶存在于细胞外培养基中时，hPIV -4表现为多步生长。然而，在L929细胞中，不完全复制的原因可能是缺乏其他未知因素。少

cDNAs encoding human parainfluenza virus type 4B (hPIV-4B) haemagglutinin-neuraminidase (HN) protein were cloned and the nucleotide sequences were determined. A high degree of identity (81.4%) was observed between the nucleotide sequences of hPIV -4A and 4B HN proteins, and 87.3% identity was found between the deduced amino acid sequences. This degree of identity is considered to be greater than the immunological similarity between hPIV -4A and -4B HN proteins determined using mAbs. To elucidate the causes of the antigenic difference between HN proteins of hPIV-4A and -4B, we constructed three cDNAs of hPIV -4B HN whose potential N-glycosylation sites were partially or completely the same as in hPIV -4A HN cDNA. We compared the antigenicity of the expressed wild type and mutant proteins, and found that the antigenicities of the mutant hPIV -4B HN proteins were more similar to the hPIV -4A HN protein than to the non-mutant hPIN -4B HN protein. This study indicated that the antigenic div … More ersity between hPIV -4A and -4B was partly caused by deletion or creation of glycosylation sites, showing that the point mutations resulting in deletion or creation of glycosylation sites in one of the initial steps leading to the division of virus into subtypes.Human parainfluemza virus type 4A (hPIV -4A) and type 4B (hPIV -4B) were tested for their ability to replicate in the monkey kidney LLC-MK2 cell line (MK2 cells) and the murine L929 cell line (L929 cells). Both MK2 cells and L929 cell line(L929 cells). Both MK2 cells and L929 cells were non-permissive for replication of hPIV -4. Acetylated trypsin was effective for the virus replication in MK2 cells, but less effective in L929 cells. Interferon (IFN) produced endogeneously played no role in their replication in L929 cells. Synthesis of virus specific polypeptides was suppressed in L929 cells HN -mTNA was not detected. These results indicate that hPIV -4 can infect both MK2 cells and L929 cells. In MK2 cells, when protease exists in the extracellular medium, hPIV -4 exhibits multistep growth. In L929 cells, however, the cause of incomplete replication might be lack of other unknown factors. Less