García M, Riblet S M
The University of Georgia, Department of Avian Medicine, Athens 30602, USA.
Avian Dis. 2001 Jul-Sep;45(3):558-66.
Infectious laryngotracheitis (ILT) is a severe acute respiratory disease of chickens caused by ILT virus. To better understand the epidemiology of the disease, a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) assay of the glycoprotein E gene has been developed and utilized to characterize vaccine strains and outbreak-related isolates. Enzymes EaeI and DdeI were used to differentiate the tissue culture origin (TCO) vaccine from chicken embryo origin (CEO) vaccines. Two RFLP patterns were observed with enzyme EaeI, one characteristic of the TCO vaccine and a second characteristic of all CEO vaccines. Three RFLP patterns were observed with enzyme DdeI. Patterns A and B were characterized as single patterns, whereas the type C pattern was a combination of patterns A and B. Analysis of vaccine strains showed the presence of patterns A and C. Pattern A was observed for the TCO vaccine and one CEO vaccine, whereas pattern C was observed for five of the six CEO vaccines analyzed. PCR-RFLP analysis of plaque-purified virus from pattern C CEO vaccine preparations demonstrated the presence of two populations (patterns A and B). Identification of molecularly different populations of viruses within currently used ILT vaccine is the first step to develop better molecular epidemiologic tools to track vaccine isolates in the field.
传染性喉气管炎（ILT）是由ILT病毒引起的鸡的一种严重急性呼吸道疾病。为了更好地了解该疾病的流行病学，已开发并利用糖蛋白E基因的聚合酶链反应（PCR）-限制性片段长度多态性（RFLP）分析来鉴定疫苗株和与疫情相关的分离株。使用EaeI和DdeI酶来区分组织培养源（TCO）疫苗和鸡胚源（CEO）疫苗。用EaeI酶观察到两种RFLP模式，一种是TCO疫苗的特征模式，另一种是所有CEO疫苗的特征模式。用DdeI酶观察到三种RFLP模式。模式A和B被表征为单一模式，而C型模式是模式A和B的组合。对疫苗株的分析显示存在模式A和C。在TCO疫苗和一种CEO疫苗中观察到模式A，而在所分析的六种CEO疫苗中的五种中观察到模式C。对来自C型CEO疫苗制剂的噬斑纯化病毒进行PCR-RFLP分析表明存在两个群体（模式A和B）。鉴定当前使用的ILT疫苗中分子不同的病毒群体是开发更好的分子流行病学工具以追踪田间疫苗分离株的第一步。
