鸡源禽流感病毒H6N6亚型在猪呼吸道组织的复制及其基因特点

Replication and genetic characteristics of chicken-originated H6N6 subtype avian influenza virus in swine respiratory tissues

目的:探讨H6N6亚型禽流感病毒(AIV)是否跨种间屏障传播感染猪及其基因特点。方法:将3株鸡源性H6N6亚型AIV体外感染猪呼吸道组织,观察病毒在猪呼吸道组织复制及其病理变化,同时应用基因测序法,比较H6N6亚型AIV各基因片段的变化,筛选H6N6亚型AIV在猪复制的基因特点。结果:病毒体外接种猪呼吸道组织后病毒分离阳性,肺局部细胞出现坏死,肺泡细胞内病毒核蛋白(NP)抗原阳性,其中A/CK/ZZ/346/2014(ZZ346)病毒株复制能力较强。基因测序和分析显示,H6N6亚型AIV的血凝素(HA)裂解位点模式属低致病性病毒,ZZ346病毒株HA出现P186T突变、HA的158位点有氨基酸缺失以及神经氨酸酶(NA)颈区出现11个氨基酸(59~69)缺失。结论:鸡源性H6N6亚型AIV可感染猪;H6N6病毒HA出现P186T突变、HA158位点出现氨基酸缺失以及NA颈区出现11个氨基酸(59~69)缺失有助于病毒在猪体内有效复制。

Objective: To investigate whether H6N6 subtype avian influenza virus(AIV)can cross interspecies barrier to infect swine and analyze its genetic characteristics.Methods: Three strains of chicken-originated H6N6 subtype AIV were infected in vitro to swine respiratory tissues,then observed the virus replication and pathological changes.At the same time,the gene sequencing method was used to compare the changes of various gene fragments of H6N6 subtype AIV,and to identified the gene characteristics of H6N6 subtype AIV replication in swine.Results: After in vitro inoculation of swine respiratory tissue,the virus was isolated and positive,local lung cells showed necrosis,and the virus nucleoprotein(NP)antigen in alveolar cells was positive.A/CK/ZZ/346/2014(ZZ346)virus strain had strong replication ability.Gene sequencing and analysis showed that the hemagglutinin(HA)cleavage site pattern of H6N6 subtype AIV was a low pathogenicity virus.P186 T mutation was found in the HA of ZZ346 strain,amino acid deletion was found in the 158 site of HA,and 11 amino acids(59-69)were missing in the neck region of neuraminidase(NA).Conclusion: In summary,our results indicated the chicken-originated H6N6 subtype AIV can infect swine.The P186 T mutation,an amino acid deletion at site of 158 in HA,and 11 amino acids deletion(position 59-69)in NA neck region help H6N6 viruses to replicate in swine.