Molecularepidemiology of Parainfluenza virus type 4 infection

采集约250份人血清，采用酶联免疫吸附试验(EL ISA)进行分析。我们发现，大约有20份血清对人类副流感4型病毒(HPIV-4)呈阳性。相同的血清对HPIV-4具有中和活性。然而，无法区分血清是否抑制了HPIV-4A或4B的生长。由于HPIV-4A和4B HN蛋白在抗原性上存在较大差异，我们建立了表达HPIV-4A或4B HN蛋白的L929细胞株，以分析HPIV-4A或4B感染是由HPIV-4A还是4B引起的。为阐明HPIV-4A和HPIV-4B抗原差异的原因，构建了3个HPIV-4B HN基因突变克隆，并建立了表达HPIV-4B突变HN蛋白的L929细胞系。用抗HPIV-4的单抗对L929细胞进行抗原性分析，结果表明糖结合位点可能是HPIV-4A和4B HN蛋白抗原差异的部分原因。

About 250 human sera were collected, and they were analyzed by enzyme linked-immunosorbent assay (ELISA). We found that about 20 sera were positive for human parainfluenza type 4 virus (HPIV-4). The same sera had neutralization activity against HPIV-4. However, it was impossible to distinguish whether the sera inhibited HPIV-4A or 4B growth. To analyze whether the infection was caused by HPIV-4A or 4B,we established L929 cell lines which express HN proteins of HPIV-4A or 4B,because there was a big antigenic difference between HPIV-4A and 4B HN proteins. The identification is now in progress.To elucidate the cause of the antigenic difference between HPIV-4A and 4B,3 mutated clones of 4B HN gene were constructed, and we established L929 cell lines which express the mutated HN proteins of HPIV-4B.The antigenicity was analyzed by flow cytometry using monoclonal antibodies against HPIV-4, and it was indicated that the sugar binding sites may in part contribute to the antigenic difference between HPIV-4A an 4B HN proteins.