Purification and characterization of recombinant human macrophage colony-stimulating factor and generation of a neutralizing antibody useful for Western analysis

Recombinant human macrophage colony-stimulating factor 1 (rCSF-1, also known as M-CSF) has been purified in milligram quantities from culture supernatants of SV40-infected CV-1 monkey cells that were transformed with a plasmid (pcCSF17) containing a human CSF-1 cDNA (Kawasaki et al. (1985) Science 230, 291–296). The rCSF-1 was purified using a 4-step procedure which resulted in a 285-fold purification and a yield of 40%. This rCSF-1 was shown to be a dimeric, disulfide-linked glycoprotein with an apparent native molecular weight of 65 kDa. The specific biological activity and amino-terminal sequence of this rCSF-1 were shown to be identical to that reported for native CSF-1 from MIA PaCa-2 cells. Although the pcCSF17 CSF-1 cDNA sequence coded for a mature polypeptide of 224 amino acids in length, C-terminal analysis of purified rCSF-1 indicated that C-terminal proteolytic processing had occurred at or near residue 158. A high-titer, polyclonal antibody to rCSF-1 was produced in rabbits and shown to specifically neutralize the biological activity of both CV-1 rCSF-1 and native CSF-1 from MIA PaCa-2 cells. In addition, the anti-CSF-1 antibody has been used to detect native and recombinant CSF-1 on Western blots.