Interferon-induced cell cycle changes in human hematopoietic cell lines and fresh leukemic cells.

A panel of 26 human hematopoietic cell lines was tested for sensitivity to growth inhibition towards interferon-alpha (IFN-alpha) by estimating the effects on cell cycle phase distribution using flow cytometry analysis. The proportion of proliferating cells was assessed by studying the fractional increase of cells in mitosis during a 24-hr vinblastine block. Of 26 cell lines tested, 17 were sensitive to IFN-alpha, and the main cell cycle effect was accumulation in the G0-G1 phase. One Burkitt's lymphoma line, Namalwa, showed a decreased rate of progress through S without any G0/G1 accumulation. Three of the cell lines were also tested with IFN-beta and with IFN-alpha 2 produced by recombinant DNA technology. The latter IFN did not affect one of the cell lines; otherwise, the results were similar to those of IFN-alpha. Six of 16 clinical specimens from patients with hematopoietic neoplasias were IFN-sensitive, all displaying a G0-G1 block. Our results indicate that IFN sensitivity is an individually linked property unrelated to cell origin.