Sharma J M
USDA-ARS-Regional Poultry Research Laboratory, East Lansing, Michigan 48823.
Avian Dis. 1987 Jul-Sep;31(3):570-6.
Several oncogenic and non-oncogenic isolates of Marek's disease virus (MDV) were inoculated into embryonated eggs on embryonation day (ED) 16 to 18, and embryos or chicks hatching from inoculated eggs were examined for infectious virus and viral internal antigen (VIA) in lymphoid organs. There was no evidence of extensive replication of MDV in any of the embryonic tissues examined. Levels of VIA peaked 4-5 days after chicks hatched. This indicated that MDV remained inactive during embryonation and did not initiate pathogenic events until chicks hatched. Because HVT replicated rapidly in the embryo but MDV did not, in ovo inoculation of HVT simultaneously with oncogenic MDV or several days after MDV resulted in significant protection (P less than 0.025) of hatched chicks against Marek's disease (MD). Little protection was obtained if HVT was given simultaneously with MDV or after MDV to chicks already hatched. The relative susceptibility of the embryo to extensive replication of the vaccine virus but not the challenge virus apparently accounted for protection against MD in chicks hatching from dually infected eggs.
将几种致癌性和非致癌性马立克氏病病毒（MDV）毒株接种到孵化第16至18天的鸡胚中，对接种后孵化出的胚胎或雏鸡的淋巴器官进行传染性病毒和病毒内部抗原（VIA）检测。在所检测的任何胚胎组织中均未发现MDV广泛复制的迹象。VIA水平在雏鸡孵化后4至5天达到峰值。这表明MDV在胚胎发育期间处于非活性状态，直到雏鸡孵化才引发致病事件。由于禽痘病毒（HVT）在胚胎中快速复制而MDV则不然，在卵内同时接种致癌性MDV或在接种MDV几天后接种HVT，可使孵化出的雏鸡对马立克氏病（MD）产生显著保护作用（P<0.025）。如果在雏鸡已孵化后同时给予HVT和MDV或在给予MDV后给予HVT，则几乎得不到保护。胚胎对疫苗病毒而非攻毒病毒广泛复制的相对易感性显然是双感染卵孵化出的雏鸡对MD产生保护作用的原因。
