[Effect of interferons on the activity of human tumor degeneration factor (TDF)]

KB cells were cultivated in the well with tumor-degenerating factor (TDF) and the natural and recombinant interferons. TDF alone induced the degenerative changes of the KB cells and formed the cell-free area, but the interferons alone did not induce the changes and did not form the cell-free area. When KB cells were cultivated with TDF and natural interferons (HuIFN-alpha, -beta and -gamma), the cell-free area was enlarged. Particularly, HuIFN-gamma enhanced the TDF activity most strongly. The recombinant interferons (HuIFN-alpha, -beta and -gamma) also augmented in the same ways as the natural interferons.