龙胜凤鸡中一株A亚群禽白血病病毒的基因组分析及其对SPF鸡的致病性研究

Sequence analysis and pathogenic study of a subgroup A avian leukosis virus isolated from Longshengfeng chickens

为了解中国地方品系鸡中禽白血病病毒(ALV)的基因组序列特征及其致病性,本研究通过DF-1细胞接种、间接免疫荧光和PCR等方法,从某龙胜凤鸡保种鸡群的种蛋中分离到一株A亚群ALV(ALV-A),命名为SDAU14A1株,并对其全基因组进行测序。将该序列与不同参考病毒株进行序列对比,结果显示SDAU14A1分离株与日本矮脚鸡分离株Tym S_90全基因组同源性最高,其U3区同源性达到100%,而与其它中国地方品系鸡分离株同源性较低。人工感染试验显示该病毒分离株感染SPF鸡后不仅引起感染鸡的生长迟缓和免疫抑制,还能够诱发淋巴细胞肿瘤,特别是具有较强的水平传播能力。本研究有助于了解我国地方品系鸡群中ALV-A的分子演变及其致病性,为我国地方品系中ALV净化提供参考依据。

To investigate the genomic features of avian leukosis virus （ALV） isolated from Chinese local chicken breeds, a subgroup A ALV （ALV-A） was isolated from ALV p27 antigen positive serum collected from a Longsheng Feng chicken farm and identified by immunofluorescence assay and PCR, designated SDAU14A1. Four pairs of primers were designed according to the published sequences of reference strains, and the whole proviral genome of SDAU14A1 was amplified by PCR and assembled using DNAStar software. Multiple sequences alignment and phylogeny evolution analysis with other reference strains. The results showed that the whole proviral genome of SDAU14A1 had the closest phylogenetic relationship with Tyms_90, a recombinant ALV associated with fowl glioma in layer chickens in Japan, with a homology as high as 100% in U3 region. However, SDAU14A1 had a distant relationship with other strains isolated earlier from different types of Chinese local breed chickens, which implied that SDAU14A1 might be a representative strain existed in local breed chickens in East Asia region. The pathogenicity of SDAU14A1 was tested by inoculating though yolk sac and intraperitoneally on SPF chickens. It indicated that SDAU14A1 infection induce lymphocytoma and subclinical traits like growth retardation and immunosuppression. These data revealed that classical subgroup ALVs like ALV-A/B were existed and prevalent in some of the Chinese local breed chickens.