Biologic and binding activities of IFN-alpha subtypes in ACHN human renal cell carcinoma cells and Daudi Burkitt's lymphoma cells

Nine interferon-alpha subtypes, IFN-alpha 1, IFN-alpha 2, IFN-alpha 5, IFN- alpha 7, IFN-alpha 8, IFN-alpha 10, IFN-alpha 14, IFN-alpha 17, and IFN-alp ha 21, were separated from purified human lymphoblastoid IFN. We tested the ir inhibitory effects on cell growth and replication of Semliki Forest viru s (SFV) and vesicular stomatitis virus (VSV) and their induction of 2',5'-o ligoadenylate synthetase (2', 5'-OAS) in ACHN renal cell carcinoma cells, I n terms of all three activities, the nine subtypes had similar relative act ivities, with IFN-alpha 10 the most active and IFN-alpha 1 the least. Their relative effects on cell growth were similar in two other human cell lines , SK-LU-1 lung cancer cells and KU-2 renal cell carcinoma cells, whereas ce lls of the Daudi Burkitt lymphoma line behaved quite differently, being hig hly sensitive to all the nine subtypes, The relative effects with ACHN cell s correlated well with their relative binding affinities. However, each of the subtypes bound to both ACHN and Daudi cells to almost the same extent. This suggests that their profound inhibitory effects on the growth of Daudi cells are amplified at some stage in the signal transduction pathway or in the expression of genes that results from binding to the IFN-alpha recepto r.