A Study On The Expression And Secretion Of Tumor Necrosis Factor And Its High Activity Mutant

Tumor Necrosis Factor (TNF), a multifunctional cytokine mainly secreted by macrophages, was originally observed in sera of mice and rabbit which had been infected with Bacille Calmette-Guerin (BCG) and subsequently treated with lipopolysaccharide of Escherichia coli. It was so named because the sera induced hemorrhagic necrosis in certain animal tumors and in some hetreotransplanted human tumors. TNF exhibits a cytolytic or cytostatic effect in a broad range of animal and human transformed cell lines in vitro but seems innocuous to non-transformed cell lines or normal embryo fibroblasts.Besides its tumoricidal activity, TNF also displays antiviral activity, inhibits the replication of various viruses and induces the cultured cells to a cellular antiviral states. Resent observtions showed that TNF still have several other activities including activating immuno-effective cells such as macrophages, polymorphonuclear leukocytes and T and B lymphacytes,increasing their cytotoxic and phagocytic activities, inducing the expression of major histocompatible complex antigen, inducing differentiation and enhancing the function of immune system agaist different pathogenic microbes invaded. So TNF is potential as an ntifumor. antiviral and immunomodulater. Phase I and II clinical trials of recombinant human tumor necrosis factor in malignancy are underway in some courtries such as USA, Germany and Japan and the initial...