Lidbury B A, Rathjen D A, Ramshaw I A, Cowden W B
Division of Cell Biology, John Curtin School of Medical Research, Australian National University, Canberra.
Biotechnol Ther. 1994;5(1-2):27-45.
This study examines the interaction of TNF with its receptor(s) in the presence of antibodies which have been previously found to enhance the in vivo antiviral and antitumor activities of this cytokine. The presence of Mab 32 has been previously shown to enhance the binding of 125I-TNF to the surface L929 cells (13), and this property was also found in the present study for HeLa cells. In addition to this, Mab 32 was found to enhance the internalization of the TNF ligand into both L929 and HeLa cells compared to control treated cultures. The consequences of such enhanced TNF-binding on TNF antiviral activity were examined in both L929 cells and HeLa cells. It was discovered that the similarities in antibody-enhanced TNF binding and internalization contrasted dramatically with the sensitivities of these two cell lines to the antiviral actions of TNF, both with and without Mab 32 (viz., L929 cells were sensitive; HeLa cells were resistant). It has been proposed that the modulation of TNF-R expression, particularly by IFNs, is an important factor in TNF's biological effects. It has been shown that the presence of IFN-gamma, with TNF plus specific enhancing antibodies, further augmented antiviral activity in vivo (13). This finding stimulated interest in examining IFN-gamma modulation of TNF-R as a factor in the antiviral activity of TNF. The expression of TNF receptor(s) in TNF- and/or IFN-gamma-exposed cells, both with and without HSV-1 infection, was therefore examined. TNF alone could induce a dose-dependent increase in receptor expression which was not significantly increased by Mab 32. Exposure of L929 cells to IFN-gamma alone also induced TNF receptor expression in mock-infected cells. HSV-1 infection of L929 cells resulted in a significant upregulation of TNF-R expression which was reversed if the cells had been preexposed to IFN-gamma. The inclusion of TNF with IFN-gamma before infection restored TNF-R expression but did not show any further synergistic or additive effects on TNF-R expression. Some minor increases in TNF-R expression were seen if Mab 32 was included with these two cytokines.
本研究检测了在先前已发现可增强该细胞因子体内抗病毒和抗肿瘤活性的抗体存在的情况下，肿瘤坏死因子（TNF）与其受体之间的相互作用。先前已表明单克隆抗体32（Mab 32）可增强125I-TNF与表面L929细胞的结合（13），本研究在HeLa细胞中也发现了这一特性。除此之外，与对照处理的培养物相比，发现Mab 32可增强TNF配体向L929和HeLa细胞内的内化。在L929细胞和HeLa细胞中均检测了这种增强的TNF结合对TNF抗病毒活性的影响。结果发现，抗体增强的TNF结合和内化的相似性与这两种细胞系对TNF抗病毒作用的敏感性形成了鲜明对比，无论有无Mab 32（即，L929细胞敏感；HeLa细胞耐药）。有人提出，TNF受体（TNF-R）表达的调节，尤其是通过干扰素（IFN）的调节，是TNF生物学效应的一个重要因素。已表明，IFN-γ与TNF加特异性增强抗体一起存在时，可进一步增强体内抗病毒活性（13）。这一发现激发了人们对研究IFN-γ对TNF-R的调节作为TNF抗病毒活性一个因素的兴趣。因此，检测了在有和无单纯疱疹病毒1型（HSV-1）感染的情况下，暴露于TNF和/或IFN-γ的细胞中TNF受体的表达。单独的TNF可诱导受体表达呈剂量依赖性增加，Mab 32对此无明显增加作用。单独将L929细胞暴露于IFN-γ也可诱导 mock感染细胞中TNF受体的表达。L929细胞感染HSV-1导致TNF-R表达显著上调，如果细胞预先暴露于IFN-γ，这种上调则会逆转。在感染前将TNF与IFN-γ一起使用可恢复TNF-R表达，但对TNF-R表达未显示出任何进一步的协同或叠加作用。如果将Mab 32与这两种细胞因子一起使用，则可观察到TNF-R表达有一些轻微增加。
