Lee Lucy F, Cui Xiaoping, Cui Zhizhong, Gimeno Isabel, Lupiani Blanca, Reddy Sanjay M
U.S. Department of Agriculture, Agricultural Research Service, Avian Disease and Oncology Laboratory, East Lansing, MI 48823, USA.
Virus Genes. 2005 Aug;31(1):73-80. doi: 10.1007/s11262-005-2202-2.
Marek's disease virus (MDV), a highly cell-associated oncogenic chicken herpesvirus, causes Marek's disease in domestic chickens. A unique phosphoprotein of MDV, pp38, has previously been associated with the maintenance of transformation in MDV-induced tumor cell lines. However, recently, the biological properties of a deletion mutant virus (rMd5Deltapp38) revealed that pp38 is involved in early cytolytic infection in lymphocytes but not in the induction of tumors. Thus, pp38 is important for early cytolytic infection and not for transformation. The pp38 protein of the MDV serotype 1 vaccine strain CVI988/Rispens differs by one amino acid when compared to the pathogenic strains of MDV. Monoclonal antibody, H19, recognizes all serotype 1 MDV strains except CVI988/Rispens. Previous studies have also shown that the unique pp38 epitope in CVI988/Rispens induced high antibody response. In order to study the role of this epitope in the protective properties of CVI988/Rispens, we generated a mutant rMd5 virus in which the wild type pp38 gene has been substituted with that of CVI988/Rispens (rMd5/pp38CVI). The replication properties of rMd5/pp38CVI, both in vitro and in vivo, and tumor induction were examined. We found that the biological properties of rMd5/pp38CVI were similar to the wild type rMd5 virus with regards to in vivo replication, antibody response and tumor induction. This shows that the pp38 derived from CVI988/Rispens is not involved in protective properties as was previously suggested.
马立克氏病病毒（MDV）是一种高度细胞相关的致癌鸡疱疹病毒，可在家鸡中引起马立克氏病。MDV的一种独特磷蛋白pp38，以前被认为与MDV诱导的肿瘤细胞系中的转化维持有关。然而，最近，一种缺失突变病毒（rMd5Deltapp38）的生物学特性表明，pp38参与淋巴细胞的早期溶细胞感染，但不参与肿瘤诱导。因此，pp38对早期溶细胞感染很重要，而对转化不重要。与MDV的致病菌株相比，MDV 1型疫苗株CVI988/Rispens的pp38蛋白有一个氨基酸不同。单克隆抗体H19能识别除CVI988/Rispens外的所有1型MDV菌株。先前的研究还表明，CVI988/Rispens中独特的pp38表位可诱导高抗体反应。为了研究该表位在CVI988/Rispens保护特性中的作用，我们构建了一种突变rMd5病毒，其中野生型pp38基因已被CVI988/Rispens的pp38基因取代（rMd5/pp38CVI）。检测了rMd5/pp38CVI在体外和体内的复制特性以及肿瘤诱导情况。我们发现，rMd5/pp38CVI在体内复制、抗体反应和肿瘤诱导方面的生物学特性与野生型rMd5病毒相似。这表明，如先前所认为的，源自CVI988/Rispens的pp38不参与保护特性。
