The role of growth factors and interferons in the induction of activated murine macrophages from bone marrow precursors.

The effects of growth factors and interferons on macrophages derived from bone marrow precursors were compared with those on peritoneal macrophages elicited by an inflammatory stimulus. Bone marrow cells grown in L-cell conditioned medium (Source MCSF) and post endotoxin lung conducted medium (source of GM-CSF) for 7-10 days and then treated for 2 days with either growth factor, recombinant IFN gamma or a cellular source of IFN alpha beta. These studies show that IFN gamma, but not IFN alpha beta, induce an activation phenotype (low mannose fucosyl receptor levels, high Ia, high superoxide release) in bone marrow macrophages. The phenotype of bone marrow macrophages derived in lung conditioned medium resembles that expressed by thioglycollate-elicited peritoneal macrophages.