Marek’s disease (MD) vaccines are unique in their capability to prevent MD lymphomas as early as a few days after vaccination, despite the fact that they do not eliminate virulent viruses from the host. To help understand the mechanism behind this unique MD vaccine effect, we compared the expression of MDV oncoprotein Meq among CD4+ T cells between vaccinated and unvaccinated birds. Chickens were vaccinated by an MD vaccine, herpesvirus of turkeys, and then challenged by a recombinant virulent MDV that expresses green fluorescent protein simultaneously with Meq. We found significantly fewer Meq-expressing CD4+ T cells appeared in peripheral blood mononuclear cells (PBMC) of the vaccinated birds compared to the unvaccinated birds as early as one week after the virulent virus challenge. In contrast, the quantity of virulent MDV genome remained similar in Meq– PBMC in both vaccinated and unvaccinated birds. Our results suggest that MD vaccination affects the dynamics of Meq-expressing, possibly transformed, cells while impact on the overall infection in the Meq– cells was not significant.

马立克氏病（MD）疫苗在预防接种后几天就可以预防MD淋巴瘤，尽管它们不能从宿主中消除有毒的病毒，但它们具有独特的预防能力。为了帮助了解这种独特的MD疫苗效应背后的机制，我们比较了接种和未接种禽类之间CD4 + T细胞之间MDV癌蛋白Meq的表达。用MD疫苗，火鸡疱疹病毒给鸡接种疫苗，然后用能与Meq同时表达绿色荧光蛋白的重组有毒MDV攻击鸡。我们发现，在强病毒攻击后的第一周，与未接种疫苗的禽类相比，接种疫苗的禽类的外周血单核细胞（PBMC）中出现的表达Meq的CD4 + T细胞明显减少。相反，在Meq–PBMC中，无论接种过或未接种过的禽类，MDV毒性基因组的数量均保持相似。我们的结果表明，MD疫苗接种会影响表达Meq的细胞（可能是转化的）的动力学，而对Meq–细胞的总体感染的影响并不显着。