鸽副黏病毒经鸡胚传代引起毒力和F基因序列变化的研究

Passaging of a pigeon paramyxovirus in chicken embryo results in virus virulence and F gene sequence

为研究鸽副黏病毒ND167在SPF鸡胚传代中毒力和F基因序列变化,运用有限稀释法将ND167连续传代扩繁,每代次均选择病毒稀释度最高且血凝价最高的尿囊液进行传代,共传10代次,测定第1、5和10代次的最小致死量致死鸡胚的平均时间(MDT)、1日龄雏鸡脑内致病指数(ICPI)和F基因序列。结果表明,ND167在鸡胚传代过程中F蛋白裂解位点氨基酸虽未突变,但是毒力却在逐渐增强,从中等毒力株演变为强毒力株。说明对于PPMV毒力判定需要根据动物实验进行,需警惕PPMV在鸡群中反复传代引起毒力增强。

In order to study the virulence and F gene sequence of ND167 in 10-day-old specific-pathogen-free(SPF)chicken embryos,the virus was passaged by chicken embryo Limit dilution method.Allantonic fluid with the highest dilution rate and hemagglutiantion titer was chosen for further Limit dilution.We purified ND167 for 10 generations,and the MDT,ICPI and F gene sequences of the 1st,5th and 10th generation were determined.The results showed that the amino acid of F protein cleavage site in ND167 was not changed and no significant mutation was found during the purification,but the virulence was gradually increased from medium virulent strain to highly virulent strain.This result suggests that the researchers should determine PPMV virulence based on animal experiments and be alert to the increased virulence of PPMV in the flocks caused by repeated passage.