H3N2亚型猪流感病毒中国分离株的克隆纯化及生物学特性

以有限稀释克隆法对29株H3N2亚型猪流感病毒(SIV)不同地区分离株进行纯化，并对其生物学特性进行了研究。结果，8株对鸡呈现中等致病力，21株对鸡呈现低致病力。不同地区SIV分离株(第5代)的EID50差异较大，以安徽分离株最高，为10^-10.77／0．2mL，其他毒株在10^-5.5～10^-10.56／0．2mL之间。黑龙江省分离株和浙江省分离株的LD50高达10^-2.84／0．1mL，其他分离株在10^-1.17～10^-2.56／0．1mL之间。经鸡胚分离传代后，SIV分离株均能凝集0．7％人“O”型血、绵羊、兔、豚鼠、小鼠、大鼠及鸡的红细胞，其红细胞凝集谱的差异主要表现在对马、牛、驴、猪红细胞的凝集特性上。大部分SIV分离株为热不稳定型，部分毒株表现为中等热稳定型和热稳定型。从其抗原特性看，大部分SIV分离株表现为亲和相，对AIV参考毒株DKUK63和SIV参考毒株SWTN77表现出较高的HI滴度；部分分离株经鸡胚传代后，出现了相别的变异。

Cloning Purification and Biological Characteristics of Swine Influenza H3N2 Subtype Virus Isolated from China

Twenty nine H3N2 subtype swine influenza viruses(SIV) isolates were purified with limited dilution cloning.The maximal diluted concentration and HA titers of the SIV strains were between 10 -4 and 10 -15 and between 256 and 4 096 ,respectively.Pathogenicity indices revealed that none of the SIV prevailing in different regions in China was highly pathogenic to chickens,with 8 strains showing moderate and the remaining 21 strains showing low pathogenicity.EID 50 of the SIV isolates(5 th generation) varied greatly with the highest value of 10 -10 77 /0 2 mL from Anhui Province and the others in the range of 10 -5 5 10 -10 56 /0 2 mL.The LD 50 of SIV was in the range of 10 -1 17 10 -2 84 /0 1 mL.Large variations in hemagglutinin thermostability of these isolates were detected,with 22 being thermolabile,2 moderately thermostabile and 5 thermostabile.All SIV isolates were capable of agglutinating human type O,sheep,rabbit,guinea pig,mouse,rat and chicken erythrocytes.The differences in hemagglutination spectrum among SIV isolates mainly showed in the agglutination of horse,cattle,donkey and pig erythrocytes.Large differences in antigenic features were detected in SIV isolates from different regions.Different isolates from the same region were also different in antigenic features,but still produced high HI titers against homologous and other homologous and was judged as displaying affinity phase.The majority of SIV strains showed relatively high HI titers against DKUK63 and SWTN77 strains,and also some inhibition against DKAT69 and SWCO77 strans.The HI titers against H3 subtype were generally 1 6 titers higher than that against H1 subtype.Some SIV isolates exhibited phase deviation after being transfered in chicken embryo.