【摘要】 为明确泰和乌鸡种鸡场外源性禽白血病病毒(ALV)的感染现状及其优势亚群的基因组序列及致病性特征，本研究通过ELISA检测血液样品中ALV p27抗原，并进行了病毒分离与鉴定。结果得到1株ALV(TH240808-1)。ELISA检测结果显示，调研种鸡群的外源性ALV阳性率为11.5%,提示该场存在ALV感染，同时，发现该鸡场存在J、K亚群共感染，并且J亚群是主要流行的亚群。env序列分析表明TH240808-1属于J亚群，与J亚群参考株核苷酸一致性为89.9%～95.6%。基因组分析显示，该毒株具有典型复制C型反转录病毒结构，基因组全长为7 652 bp,含完整gag(2 106 bp)、pol(2 622 bp)和env(1 734 bp)开放阅读框，两侧为325 bp长末端重复序列(LTRs)。进一步分析发现，该毒株3′UTR存在205 bp连续缺失，U3区调控元件完全保守，且与蛋鸡源J亚群毒株具有相似突变位点。通过卵黄囊接种7日龄SPF鸡胚构建垂直感染模型，证实该毒株有致病性：感染胚孵化率显著降低，且呈现肝脏多灶性坏死及胚胎发育异常，免疫组化试验证实肝脏病毒增殖，3日龄雏鸡体质量差异极显著(P<0.01),胸腺和法氏囊指数分别于第2周(P<0.01)、第3周(P<0.05)显著下降。本研究首次报道泰和乌鸡源ALV-J的全基因组结构及其致病性，为了解ALV-J在中国的流行及其致病性提供了参考数据。更多还原

【Abstract】 To clarify the infection status of exogenous avian leukosis virus(ALV) in the breeding stock of Taihe silky fowls and the genomic sequence and pathogenicity characteristics of the virus dominant subgroups,this study detected ALV p27 antigen in blood samples using ELISA and performed virus isolation and identification.A strain of ALV(TH240808-1) was obtained.ELISA results showed that the positive rate of exogenous ALV in the surveyed breeding flock was 11.5%,indicating the presence of ALV infection in this farm.Simultaneously,co-infection with subgroups J and K was identified,with subgroup J being the predominant circulating strain.Env sequence analysis revealed that TH240808-1 belongs to subgroup J,sharing 89.9%-95.6% nucleotide identity with reference strains of subgroup J.Genomic analysis demonstrated that this strain exhibits the typical structure of a replication-competent type Cretrovirus,with a full genome length of 7 652bp,containing complete open reading frames of gag(2 106 bp),pol(2 622 bp),and env(1 734 bp)genes,flanked by 325 bp long terminal repeats(LTRs).Further sequence analysis identified a continuous 205 bp deletion in the 3’UTR,while the regulatory elements in the U3 region were fully conserved,and the strain shared similar mutation sites with subgroup J strains originating from layer chickens.A vertical infection model was established by inoculating 7-day-old SPF chicken embryos with TH240808-1 via the yolk sac,confirming the pathogenicity of the isolate:the hatching rate of infected embryos was significantly reduced,accompanied by multifocal necrosis in the liver and abnormal development of infected embryos.Immunohistochemistry confirmed viral proliferation in the liver.Relative body quality differences in 3-day-old chicks were highly significant(P<0.01),and thymus and bursa indices showed significant decreases at the 2nd week(P<0.01) and3rd week(P<0.05),respectively.This study was the first to report the full genomic structure and pathogenicity of ALV-J derived from Taihe silky fowls,providing reference data for understanding the prevalence and pathogenicity of ALV-J in China.更多还原