TUMOR NECROSIS FACTOR INDUCES A NEW REGULATORY CYTOKINE

人肿瘤坏死因子诱导一种新的调节性细胞因子 融合的二倍体人成纤维细胞(FS-4株)的“老化”培养。这个 由肿瘤坏死因子诱导这种新的细胞因子，称为干扰素-β2(干扰素-β2)， 代表一种调节细胞增殖的自分泌反馈机制。 重组人肿瘤坏死因子促进FS-4细胞增殖 通过加入中和抗体可以进一步增强这种效果。 对肿瘤坏死因子处理的培养物中的干扰素-β的影响。肿瘤坏死因子还具有抗病毒作用。 在被干扰素-β抗体阻断的FS-4细胞中。 对经肿瘤坏死因子处理的细胞的mRNA进行印迹杂交分析表明 诱导出新的干扰素-β2基因。其他生长因子(牛血清和 PDGF)也可诱导产生干扰素-β2。这些观察结果提出了这样一种可能性 肿瘤坏死因子的其他生物学活性也可能是通过诱导 干扰素-β2。与新的1.3kb干扰素-β2mRNA相对应的cDNA3 被克隆、ITS核苷酸序列测定、ITS氨基酸序列测定 并将其多态基因克隆到人类7号染色体上。 在大肠杆菌中表达干扰素-β2的实验正在进行中。我们将探索 诱生干扰素-β2的生物化学和细胞生理学 人成纤维细胞经肿瘤坏死因子诱导。关键实验也将在 适当的小鼠系统。我们建议完成我们对 肿瘤坏死因子诱导FS-4细胞中人干扰素-β2基因和蛋白的结构 并确定稳定状态增加的分子基础 肿瘤坏死因子对成纤维细胞干扰素-β2基因表达的影响我们会 评价人类人类白细胞抗原I类基因表达是否增加 重组肿瘤坏死因子对成纤维细胞脂蛋白脂酶活性的影响 肿瘤坏死因子处理的小鼠前脂肪细胞的活性及其细胞毒作用 肿瘤坏死因子在某些人肿瘤细胞系和合适的小鼠肿瘤模型中的作用 也可能涉及诱导干扰素-β2。的功能后果 人干扰素-β2基因的多种多态形式与细胞类型 还将探讨其表达在对肿瘤坏死因子的反应中的特异性。 这些研究可能会提供对使用 肿瘤坏死因子和干扰素-β2等生物反应调节剂在临床上的应用 对抗肿瘤疾病。

Human tumor necrosis factor (TNF) induces a new regulatory cytokine in confluent "aged" cultures of diploid human fibroblasts (FS-4 strain). The induction by TNF of this new cytokine, called interferon-Beta2 (IFN-Beta2), represents an autocrine feedback mechanism regulating cell proliferation. Recombinant human TNF increases cell proliferation in FS-4 cell cultures. This effect can be enhanced further by inclusion of neutralizing antibodies to IFN-Beta in TNF-treated cultures. TNF also exerts an antiviral effect in FS-4 cells which is blocked by antibodies to IFN-Beta. Blot-hybridization analyses of mRNA from TNF-treated cells show that TNF induces the novel IFN-Beta2 gene. Other growth factors (bovine serum and PDGF) also induce IFN-Beta2. These observations raise the possibility that other biological activities of TNF may also be mediated by the induction IFN-Beta2. The cDNA corresponding to the novel 1.3 kb IFN-Beta2 mRNA has been cloned, its nucleotide sequence determined, its amino acid sequence deduced and its polymorphic gene cloned and assigned to human chromosome 7. Experiments are underway to express IFN-Beta2 in E. coli. We shall explore the biochemistry and cellular physiology of the induction of IFN-Beta2 in human fibroblasts by TNF. Key experiments will also be carried out in appropriate murine systems. We propose to complete our studies of the structure of the human IFN-Beta2 mRNA and protein induced by TNF in FS-4 cells and to determine the molecular basis for the increase in steady-state levels of IFN-Beta2 mRNA in fibroblasts treated with TNF. We shall evaluate whether the increased expression of class I HLA genes in human fibroblasts exposed to recombinant TNF, the decreased lipoprotein lipase activity in TNF-treated murine preadipocytes, and the cytotoxic effects of TNF on some human tumor cell lines and in appropriate murine tumor models may also involve induction of IFN-Beta2. The functional consequences of the various polymorphic forms of the human IFN-Beta2 gene and the cell-type specificity of its expression in response to TNF will also be explored. These studies are likely to provide insights important to the use of biological response modifiers such as TNF and IFN-Beta2 in the clinic against neoplastic diseases.