Kaye K M, Izumi K M, Li H, Johannsen E, Davidson D, Longnecker R, Kieff E
Department of Medicine, Harvard Medical School, Channing Laboratory, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
J Virol. 1999 Dec;73(12):10525-30. doi: 10.1128/JVI.73.12.10525-10530.1999.
An Epstein-Barr virus (EBV) recombinant (MS231) that expresses the first 231 amino acids (aa) of LMP1 and is truncated 155 aa before the carboxyl terminus transformed resting B lymphocytes into lymphoblastoid cell lines (LCLs) only when the infected cells were grown on fibroblast feeder cells (K. M. Kaye et al., J. Virol. 69:675-683, 1995). Higher-titer MS231 virus has now been compared to wild-type (WT) EBV recombinants for the ability to cause resting primary B-lymphocyte transformation. Unexpectedly, MS231 is as potent as WT EBV recombinants in causing infected B lymphocytes to proliferate in culture for up to 5 weeks. When more than one transforming event is initiated in a microwell, the MS231 recombinant supports efficient long-term LCL outgrowth and fibroblast feeder cells are not required. However, with limited virus input, MS231-infected cells differed in their growth from WT virus-infected cells as early as 6 weeks after infection. In contrast to WT virus-infected cells, most MS231-infected cells could not be grown into long-term LCLs. Thus, the LMP1 amino-terminal 231 aa are sufficient for initial growth transformation but the carboxyl-terminal 155 aa are necessary for efficient long-term outgrowth. Despite the absence of the carboxyl-terminal 155 aa, MS231- and WT-transformed LCLs are similar in latent EBV gene expression, in ICAM-1 and CD23 expression, and in NF-kappaB and c-jun N-terminal kinase activation. MS231 recombinant-infected LCLs, however, require 16- to 64-fold higher cell density than WT-infected LCLs for regrowth after limiting dilution. These data indicate that the LMP1 carboxyl-terminal 155 aa are important for growth at lower cell density and appear to reduce dependence on paracrine growth factors.
一种表达潜伏膜蛋白1（LMP1）前231个氨基酸且在羧基末端前截短155个氨基酸的爱泼斯坦-巴尔病毒（EBV）重组体（MS231），只有当感染细胞在成纤维细胞饲养层细胞上生长时，才能将静止的B淋巴细胞转化为淋巴母细胞系（LCLs）（K.M.凯伊等人，《病毒学杂志》69:675 - 683，1995年）。现已将更高滴度的MS231病毒与野生型（WT）EBV重组体在引起静止原代B淋巴细胞转化的能力方面进行了比较。出乎意料的是，MS231在使感染的B淋巴细胞在培养中增殖长达5周方面与WT EBV重组体一样有效。当在微孔中引发不止一个转化事件时，MS231重组体支持高效的长期LCL生长，并且不需要成纤维细胞饲养层细胞。然而，在病毒输入有限的情况下，早在感染后6周，MS231感染的细胞在生长方面就与WT病毒感染的细胞有所不同。与WT病毒感染的细胞相反，大多数MS231感染的细胞无法生长为长期LCLs。因此，LMP1氨基末端的231个氨基酸足以实现初始生长转化，但羧基末端的155个氨基酸对于高效的长期生长是必需的。尽管缺少羧基末端的155个氨基酸，MS231和WT转化的LCLs在EBV潜伏基因表达、细胞间黏附分子-1（ICAM-1）和CD23表达以及核因子κB（NF-κB）和c-jun氨基末端激酶激活方面相似。然而，在有限稀释后再生长时，MS231重组体感染的LCLs所需的细胞密度比WT感染的LCLs高16至64倍。这些数据表明，LMP1羧基末端的155个氨基酸对于在较低细胞密度下的生长很重要，并且似乎降低了对旁分泌生长因子的依赖性。
