Effect of human leukocyte interferon on the growth of human osteosarcoma cells in tissue culture.

Nine osteosarcoma cell lines, originally developed from six osteosarcoma tumours in five patients, and two cell lines of non-tumour origin (glia and fibroblast) were grown in vitro in the presence of human leukocyte interferon (L-IF). L-IF exerted a dose-dependent inhibition of growth in all these lines. The inhibitory activity displayed characteristics typical of interferons. Inhibition of cell growth occurred at a much lower L-IF concentration for the osteosarcoma than for the non-tumour-derived lines. Inhibition of tumour cell growth was observed at concentrations obtained in the serum of osteosarcoma patients treated with interferon.