马立克病病毒超强毒株GX0101感染宿主部分病毒基因表达水平及致病阶段分析

The Viral Gene Expression Profiles and Pathogenic Phases of the Disease Caused by Very Virulent MDV Strain GX0101

旨在探讨马立克病病毒（MDV）超强毒株GX0101对宿主的感染过程及致病阶段,即＂Cornell模型＂,为进一步使用该毒株研究MDV的致病或致瘤机制奠定基础。用GX0101接种1日龄SPF鸡,建立了感染宿主的动物模型;然后用RT-qPCR分析10个具有代表性的MDV蛋白编码基因在感染不同时间点的动态基因转录水平。结果显示,GX0101感染发病鸡的临床症状及剖检病变与典型的马立克病一致;MDV编码的结构蛋白基因gB、gE和UL6、非结构蛋白基因UL42和UL52、立早期基因ICP4、水平传播相关基因UL13以及磷酸化蛋白基因pp38具有相似的转录水平和趋势,均在GX0101感染后7d上升至第一个峰值,10d降至低谷,14d又逐渐升高并在21d达到第二个峰值,30~60d逐渐下降并处于较低的转录水平;MDV编码的原癌基因meq和毒力相关基因RLORF6在GX0101感染7d即持续升高,并在14~60d的试验周期内较长时间处于高转录水平。结合作者此前研究及本文结果分析,GX0101感染宿主的＂Cornell模型＂：早期增殖性-限制性感染期为1~7d,潜伏感染期约为10d前后,晚期溶细胞性感染及免疫抑制期发生于14~21d,而T细胞转化及淋巴瘤形成阶段可能在14d前后就已经开始。

The present work was performed to study the infection phases of Marek＇s disease（MD）,namely‘Cornell Model＇,caused by the very virulent（vv）Marek＇s disease virus（MDV）strain GX0101.For the first step,one-day-old specific pathogen free（SPF）chickens were challenged by GX0101 to establish the animal model of MD.Then,the kinetic transrption levels of 10 representative MDV protein-coding genes at different days post-infection（dpi）were determinedby real-time quantitative PCR（RT-qPCR）.The results showed that the onset of clinical symptoms and autopsy lesions of GX0101-infected birds was consistent with the typical MD cases.Some of the MDV protein-coding genes,including the structural protein-coding genes of gB,gE and UL6,the nonstructural protein-coding genes of UL42 and UL52,the immediate early infected cell protein 4gene（ICP4）,the horizontal transmission associated gene of UL13 and the 38 kD phosphorylated protein gene（pp38）,demonstrated a similar transcription pattern,which increased to a first peak at 7dpi,fell to a bottom level at 10 dpi,increased again at 14 dpi and reached to a second peak at 21 dpi,and then gradually declined to low levels from 30 to 60dpi.However,both of the unique MDV oncogene meqand virulence related gene RLORF6 represented apersistent increasing transcription trend from 7dpi,and then kept at a higher transcription level from 14 to 60dpi.Our previous and present data indicates that the‘Cornell Model＇of MD caused by GX0101 are as blow：the early cytolytic phase occurs at 1-7dpi,the latent phase establishes at about 10 dpi and the late cytolytic and immunosuppressive phase appears at 14-21 dpi,while the T cell transformation and lymphomagenesis possibly starts at about 14 dpi.