TUMOR NECROSIS FACTOR INDUCES A NEW REGULATORY CYTOKINE

人肿瘤坏死因子（TNF）诱导一种新的调节性细胞因子， 二倍体人成纤维细胞（FS-4株）的汇合“老化”培养物。 的 TNF诱导这种新的细胞因子，称为干扰素-β 2（IFN-β 2）， 代表调节细胞增殖的自分泌反馈机制。 重组人TNF增加FS-4细胞培养物中的细胞增殖。 这种效果可以通过包含中和抗体进一步增强 在TNF处理的培养物中IFN-β。 TNF还具有抗病毒作用 在FS-4细胞中，它被IFN-β抗体阻断。 从TNF处理的细胞的mRNA的印迹杂交分析表明，TNF 诱导新的IFN-β 2基因。 其他生长因子（牛血清和 PDGF）也诱导IFN-β 2。 这些观察结果提出了一种可能性， TNF的其它生物活性也可以通过诱导 IFN-β 2。 对应于新的1.3kb IFN-β 2 mRNA的cDNA具有 已克隆，其核苷酸序列测定，其氨基酸序列 推导并克隆了其多态性基因，并将其定位于人类7号染色体。 在大肠杆菌中表达IFN-β 2的实验正在进行中。杆菌 我们将探索 IFN-β 2诱导的生物化学和细胞生理学， 人成纤维细胞的TNF。 重点实验还将在 合适的鼠系统。 我们建议完成我们对 FS-4中TNF诱导的人IFN-β 2 mRNA和蛋白的结构 细胞，并确定稳态增加的分子基础 用TNF处理的成纤维细胞中IFN-β 2 mRNA水平。 我们将 评估是否增加人类I类HLA基因的表达， 暴露于重组TNF的成纤维细胞， TNF-处理的小鼠前脂肪细胞中的活性，以及 TNF对某些人肿瘤细胞系和适当的小鼠肿瘤模型的作用 也可能涉及IFN-β 2的诱导。 的功能性后果 人IFN-β 2基因的各种多态性形式和细胞类型 还将探索其表达对TNF应答的特异性。 这些研究可能会提供重要的见解， 生物反应调节剂，如TNF和IFN-β 2在临床上 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.