Comparative antiproliferative and receptor binding activities of interferons alpha and beta on lymphoblastoid and melanoma cells

The relative antiproliferative and receptor binding characteristics of the hitherto little-characterized interferon alpha 4a on cells of lymphoid and epithelial origin are compared with two other type I interferons, alpha 2 a and beta. Using the lymphoblastoid cell line, Daudi, interferons alpha 4 a and alpha 2 b had similar antiproliferative activity, and were about 10-fold more active than IFN beta. By contrast, using the melanoma cell line Sk-Mel-28, IFN beta was the most active, whereas IFN alpha 2b and IFN alpha 4a were respectively 60-fold and greater than 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.