title: [Mechanism of postvaccinal immunity in Marek's disease].
abstract: The apathogenic variant No. 38 of Marek's disease virus, Kekava strain (MDV-Kekava), at the level of the 16th and 45th passages in vitro made chickens resistant to Marek's disease when inoculated 14 days before the infection of the chickens with the pathogenic variant No. 55 of MDV-Kekava. A simultaneous administration of both variants did not protect the animals against the disease. The occurrence in variants of MDV-Kekava of genetic markets manifest upon virus passages in chick embryo fibroblast (CEF) cultures provided an opportunity to study the interactions between them in chickens, using the CEF culture for virus isolation. The results of virus isolation from the blood cells of vaccinated chickens showed interference to occur in chickens between the virus variants as the rate of isolation of the pathogenic variant was 3 times as low as that of apathogenic MDV-Kekava, and both virus variants persisted in different cells. When chickens were inoculated simultaneously with both virus variants, the recovery rate of both pathogenic and apathogenic variants from the blood cells was similar. In such cases, persistence of two virus variants in one cell is also possible. The experimental results suggest that in the mechanism of resistance of vaccinated chickens to Marek's disease a significant role may be played by interference between the viruses in which the "occupation" of target cells by vaccine virus protects them from pathogenic MDV.
mesh_terms: D000818:Animals; D002645:Chickens; D008381:Herpesvirus 2, Gallid / Q000235:genetics; D008380:Marek Disease / Q000382:microbiology / Q000517:prevention & control*; D014611:Vaccination; D014762:Viral Interference
vernacular_title: K mekhanizmu postvaktsinal'nogo immuniteta pri bolezni Mareka.