Binding of macrophage colony-stimulating factor to serum proteins.
Although three molecular forms of macrophage colony-stimulating factor (M-CSF) have been reported, Western blot analysis of immunoaffinity-purified M-CSF from human blood has shown that the major species of M-CSF in the serum has a molecular weight (MW) of 85 kD. Superose-12 gel filtration chromatography of immunoaffinity-purified serum M-CSF showed the presence of M-CSF-positive fraction in a higher MW area compared with the elution profile of recombinant human (rh) 85-kD M-CSF. Western blot analysis of the higher MW fraction showed that the M-CSF was the same as rh 85-kD M-CSF (not proteoglycan form of M-CSF), indicating that, in the serum, M-CSF exists bound to some serum proteins. To detect the serum proteins, we performed M-CSF-bound column chromatography. The eluate contained at least three serum proteins including albumin and IgG. This result was supported by chromatography using biotinylated M-CSF and avidin-agarose. The binding between rhM-CSF and albumin or IgG was also demonstrated by high-performance liquid chromatography (HPLC) fractionation of the mixture and enzyme-linked immunosorbent assay (ELISA) of the fractions. In the serum, a fraction of M-CSF seems to be complexed with serum proteins such as albumin and IgG.
Ohtsuki
T
T
Division of Hematology, Department of Internal Medicine, Jichi Medical School, Tochigi, Japan.
Hatake
K
K
Ikeda
M
M
Yamada
M
M
Motoyoshi
K
K
Miura
Y
Y
D000818:Animals; D001798:Blood Proteins / Q000378:metabolism*; D015153:Blotting, Western; D016466:CHO Cells; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D003412:Cricetulus; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D012709:Serum Albumin / Q000378:metabolism
D001798:Blood Proteins; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D012709:Serum Albumin; D016173:Macrophage Colony-Stimulating Factor