抄録
A granulocyte colony-stimulating factor (G-CSF) was highly purified from the serum-free culture medium of RSP-2•P3 cells. The G-CSF had an apparent molecular weight of 33, 000 as determined by high speed gel permeation chromatography, but its molecular weight was decreased to 15, 000 by 0.1 % sodium dodecyl sulfate. A small amount of monocyte/macrophage CSF (M-CSF) also was separated from the same medium. The production of this M-CSF was increased markedly by bacterial lipopolysaccharides. The M-CSF had an apparent molecular weight of 77, 000 in the absence of 0.1 % SDS and 49, 000 in its presence. The G-CSF was stable against 5 mM dithioth-reitol, whereas the M-CSF was slowly inactivated. The two CSFs also differed in their heat-stability and resistance to trypsin. Neuraminidase changed the isoelectric point of both CSFs. Anti-L cell CSF serum severely inhibited the activity of M-CSF but not that of G-CSF. A 1 : 1 mixture of M-CSF and G-CSF developed colonies of the respective types, both in excess of the number predicted. The RSP-2•P3 G-CSF reported here should prove very useful in the study of differentiation in myeloid stem cells.
