Influence of interferon preparations on the proliferative capacity of human and mouse bone marrow cells in vitro.

The toxicity of interferon to bone marrow was studied by the use of in vitro colony forming assays for hemopoietic cells. In the same study the relative inhibitory effects of two clinically common interferon preparations, leukocyte and fibroblast interferons, were compared with regard to their effect on both myeloid [colony-forming unit, culture (CFUc)] and erythroid [colony-forming unit, erythroid (CFUe)] progenitor cells. CFUe formation in human bone marrow cells in vitro appeared to be fairly resistant to both interferons. Only high doses of both interferons gave a marked inhibition of CFUe. However, the toxicity of leukocyte and fibroblast interferon was divergent for CFUe in human bone marrow. Leukocyte interferon appeared to be considerably more inhibitory for CFUe than was fibroblast interferon. The effects of mouse interferon, induced in L929 cells, on the growth of CFUc and CFUe in murine bone marrow cells were comparable with those of fibroblast interferon on human cells. The toxicity of human and murine interferon was species specific. Except for the toxicity of leukocyte interferon to CFUc in human bone marrow, the toxicity of interferon was marked only with concentrations on interferon far exceeding the amount necessary to produce an antiviral state in vitro.