Effects of site-specific polyethylene glycol modification of recombinant human granulocyte colony-stimulating factor on its biologic activities.
BACKGROUND
Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is a long-chain cytokine that is administered to stimulate the production of white blood cells (WBCs) to reduce the risk of serious infection in immunocompromized patients. However, to achieve sustained stimulation of WBC production, rhG-CSF must be administered frequently, thus limiting its clinical use.


METHODS
We conjugated rhG-CSF with linear monomethoxy-polyethylene glycol (PEG) maleimide at amino acid residue Cys(17) to test our hypothesis that this could extend the in vivo half-life of rhG-CSF in blood.


RESULTS
The mono-PEG rhG-CSF became more stable to pH, temperature, and enzyme degradation in vitro, and had granulopoietic activity that was superior to the unmodified form in vivo. The granulopoietic activity of PEG-G-CSF was 2.82-fold greater than that of unmodified G-CSF.


CONCLUSIONS
These results indicate that the thiol-specific PEGylation remarkably prolonged the half-life of rhG-CSF and represents a novel strategy to address the more clinically acceptable therapeutic application of hemopoietic growth factor.
Hao
Yong
Y
State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, Nanjing University, Nanjing, People's Republic of China.
Chen
Junhui
J
Wang
Xinchang
X
Zhu
Haowen
H
Rong
Zhigang
Z
D000818:Animals; D002460:Cell Line; D016179:Granulocyte Colony-Stimulating Factor / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007962:Leukocytes / Q000187:drug effects; D051379:Mice; D011092:Polyethylene Glycols / Q000737:chemistry*; D011994:Recombinant Proteins; D013696:Temperature; D014357:Trypsin / Q000378:metabolism
D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; D011092:Polyethylene Glycols; D014357:Trypsin