接种不同毒力的马立克氏病病毒后鸡病毒血症的动态比较

1日龄非免疫鸡分别接 马立克氏病病毒（MDV）Ⅰ强毒GA株、Ⅰ型MDV疫苗毒CVI988株和Ⅲ型火鸡疱疹病毒（HVT）疫苗株后第4日起，定期采血并和抗MDV囊膜糖蛋白B(gB)单克隆抗体介导的间接免疫荧光试验检测MDV在外周因液单核细胞（PBMCs）中的感染状况。结果发现，自接种Ⅰ型强毒GA株后第4日至鸡发病死亡前，都能检出GA株引起的病毒血症，并于2周左右达到高峰；自接种CVI988株后第4日至第20日止，能检出病毒血症，并于第8天左右达到高峰；自接种HVT后第4日至第16日止，能检出病毒血症，并于第6天左右达到高峰。与此同时，将GA株病毒血症的IFA检测结果与细胞培养上病毒空班计数试验结果比较，发现IFA试验比空斑计数试验更为敏感。本试验既可用于判断对鸡作MDV疫苗免疫的接种效果，又可用于检测MDV野毒感染状态。

Comparison of Dynamics in Viremia Levels in Chickens Inoculated with Marek's Disease Virus Strains of Different Pathotypes

One day old unvaccinated chicks were inoculated with serotype I virulent strain GA and vaccine strain CVI988, serotype III vaccine strain HVT of Marek's disease viruses(MDV). By using an indirect immunofluorescence assay of suspensions of peripheral blood mononuclear cells(PBMC) with monoclonal antibodies(MAb) BA 4 and BD 8 specific to glycoprotein B of MDV, The dynamic courses of viremia levels for each of 3 strains from 4 days to 45 days postinfection (PI) were determind. Viremia for virulent strain GA infected chickens were detected from 4 days PI until days before death of infected chickens, it got its peak at about 14 days PI. Viremia in serotype 1 vaccine CVI988 inoculated chickens were measured between 4 to 22 days PI, it could be detected from 4 days PI and ended at 18 days PI, it got its peak at 8 days PI. For serotype 3 vaccine HVT inoculated chickens, viremia could be detected beween 4 to 14 days PI, its peak happened at about 6 days PI. Such IFA with MAbs BA4 and BD 8 could be used to evaluate quality of vaccination process in chicken flocks. The differential dynamic courses of viremia for different strains may be used to diagnose virulent MDV infection in vaccinated flocks. The viremia levels measured by IFA with the MAbs and co cultivation assay for plague forming unit(PFU) were compared. The results indicated that IFA assay of PBMC suspension was more sensitive and specific than co cultivation assay, i.e. viremia levels measured by IFA were 30 to 100 fold higher than that by plague forming assay in CEF for the same sample.