Differentiation of FDB1 and FDB2 cell lines in response to murine GM-CSF.

(A) Time course of proliferation of FDB cell lines. FDB1 and FDB2 cells were washed and placed in culture in the presence of IL-3 plus GM-CSF (▪), IL-3 (▴), or GM-CSF (▾) or in the absence of growth factors (⧫), and the number of viable cells was determined daily with the use of a hemocytometer. (B) Time course of viability of FDB cell lines. In the same experiment as in A, the percentage of viable FDB1 and FDB2 cells cultured in the presence of IL-3 plus GM-CSF (▪), IL-3 (▴), or GM-CSF (▾) or in the absence of growth factors (⧫) were determined from at least 200 cells scored. (C) Time course of differentiation of FDB cell lines. In the same experiment as in A, samples of FDB1 and FDB2 cells cultured in the presence of the indicated growth factors were cytocentrifuged and stained daily, and the proportion of differentiated granulocytes (▪, dashed lines), the proportion of macrophages (▴, dashed lines), and the total proportion of differentiated cells (⧫, solid lines) were determined from at least 200 cells scored microscopically.