Simon M, Melzner I, Bültmann B
Abteilung Pathologie, Universität Ulm, Federal Republic of Germany.
Arch Virol. 1989;107(1-2):45-53. doi: 10.1007/BF01313877.
Synthesis of the Epstein-Barr virus (EBV) associated early antigen (EA) can be induced by a variety of agents in Raji cells, a latently EBV-infected Burkitt lymphoma line. We investigated the role of lipoproteins in this EA induction system. Cell growth was not affected by lipoprotein-deficiency, but EA induction by most combinations of the inducers TPA (tetradecanoyl-phorbol-acetate), IdU (iododeoxyuridine), n-BA (n-butyric acid), anti-IgM and EA inducing factor (EIF), was greatly reduced. Only the inducer combination TPA/n-BA was completely independent of the presence of lipoproteins, indicating a different induction pathway. Removing the lipid moieties of the culturing serum did not result in reduced EA induction. Thus, the lowered EA inducibility in lipoprotein-deficiency is due to the absence of the protein moiety (apolipoprotein). Addition of HDL or VLDL partially reconstituted the original EA inducibility, whereas LDL had no effect. Lipoproteins were particularly important during the first 4 hours of induction, the phase where inducers may act on cell membrane structures (e.g., receptors). But lipoproteins were also required throughout the incubation period, even in a late and inducer independent phase.
在拉吉细胞（一种潜伏感染爱泼斯坦 - 巴尔病毒的伯基特淋巴瘤细胞系）中，多种因子可诱导爱泼斯坦 - 巴尔病毒（EBV）相关早期抗原（EA）的合成。我们研究了脂蛋白在该EA诱导系统中的作用。脂蛋白缺乏并不影响细胞生长，但大多数诱导剂组合（十四烷酰佛波醇乙酸酯（TPA）、碘脱氧尿苷（IdU）、正丁酸（n - BA）、抗IgM和EA诱导因子（EIF））诱导EA的能力大幅降低。只有TPA/n - BA诱导剂组合完全不依赖脂蛋白的存在，表明其诱导途径不同。去除培养血清中的脂质部分并不会导致EA诱导能力降低。因此，脂蛋白缺乏时EA诱导能力降低是由于蛋白质部分（载脂蛋白）的缺失。添加高密度脂蛋白（HDL）或极低密度脂蛋白（VLDL）可部分恢复原始的EA诱导能力，而低密度脂蛋白（LDL）则无作用。脂蛋白在诱导的最初4小时（诱导剂可能作用于细胞膜结构（如受体）的阶段）尤为重要。但在整个孵育期也都需要脂蛋白，即使是在后期与诱导剂无关的阶段。
