Comparative antiproliferative and receptor binding activities of interferons α and β on lymphoblastoid and melanoma cells

The relative antiproliferative and receptor binding characteristics of the hitherto little-characterized interferon α4a on cells of lymphoid and epithelial origin are compared with two other type I interferons, α2a and β. Using the lymphoblastoid cell line, Daudi, interferons α4a and α2b had similar antiproliferative activity, and were about 10-fold more active than IFNβ. By contrast, using the melanoma cell line Sk-Mel-28, IFNβ was the most active, whereas IFNα2b and IFNα4a were respectively 60-fold and > 1000-fold less active than on Daudi cells. Receptor binding did not correlate with antiproliferative sensitivities, but confirmed a shared receptor component for these three interferons. These results indicate that the antiproliferative activities of three type I IFNs differs markedly on different cell types and that this is unlikely to be due to receptor binding, but more likely a post receptor binding event.