猪瘟病毒浙江分离株体外生长特性及其囊膜糖蛋白E2分子的变异分析

Growth characteristics of classical swine fever virus strains isolated in Zhejiang and genetic variations of their envelope glycoprotein E2

为了研究分离于浙江省衢州和杭州的2株猪瘟病毒基因2型流行毒株QZ-07、HZ1-08在猪肾细胞(PK-15)和猪睾丸细胞(ST)中的生长特性及其囊膜糖蛋白E2的分子进化特征,采用间接免疫荧光、效价测定和进化分析等分子生物学方法将基因2型流行毒株与基因1型石门株进行了比较。结果表明,石门株在PK-15细胞中的增殖效率明显高于ST细胞;感染PK-15细胞后第48小时,细胞内的效价可达107TCID50/mL,而在ST细胞中的效价只有105.25 TCID50/mL。基因2型毒株在PK-15细胞中的增殖水平明显低于ST细胞,尤其以HZ1-08株更为明显;感染ST细胞后第48小时,细胞内的效价为105 TCID50/mL,而PK-15细胞中的效价只有102.75 TCID50/mL。两基因型毒株E2的核苷酸同源性低于90%,氨基酸同源性约为90%。表明,基因2型毒株的体外生长特性及其E2的分子特性均与基因1型毒株存在差异。

Two field strains QZ-07 and HZ1-08 of classical swine fever virus isolated from diseased pigs in Zhejiang were phylogeneticly classified as group 2. Their replication kinetics in porcine kidney 15 （PK- 15） and swine testicle（ST） cell lines were compared with the group 1 Shimen strain. The Shimen strain replicated more efficiently in PK-15 cells than in ST cells（10^7 TCID50/mL vs 10^5.25 TCID50/mL at 48 h post-infection）. In contrast, the two field strains displayed decreased replication in PK-15 cells （10^2.75 TCID50/mL for isolate HZ1-08 vs 10^5 TCIDno/mL in ST cells）. Pairwise comparisons demonstrated that the identities of E2 between the two groups were below 90% at the nucleotide level and approximately 90% at the amino acid level. The overall hydrophilicity of glycoprotein E2 was similar. This study indicates that the growth characteristics and glycoprotein E2 are different among virus strains between the two groups.