The glycosylation and in vivo stability of human granulocyte-macrophage colony-stimulating factor produced in rice cells.

Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) has been produced in several different cell types, and has different properties depending on the production process used. There has been no report of glycosylation ratio or of the role of glycans for plant cells-derived rhGM-CSF. We investigated the terminal sialylation of rhGM-CSF produced in rice cells (rrhGM-CSF) using lectins. Glycosylation ratios of rrhGM-CSF and yeast-derived rhGM-CSF (yrhGM-CSF) were evaluated by chemical deglycosylation. After intravenous administration to rats, the clearance rates of rrhGM-CSF and yrhGM-CSF as well as deglycosylated forms of them were evaluated. In vitro bioactivities of rrhGM-CSF and yrhGM-CSF were measured in dose- and time-dependent manners. Although rrhGM-CSF does not have terminal sialic acids, the glycosylation ratio was two-fold higher than that of yrhGM-CSF, and rrhGM-CSF sustained longer than yrhGM-CSF in the blood circulation. Moreover, yrhGM-CSF and rrhGM-CSF have almost same bioactivity via dose- and time-dependent manners. Deglycosylated rrhGM-CSF was cleared faster than native forms, while deglycosylated yrhGM-CSF and yrhGM-CSF were similarly cleared in blood circulation. These results suggest that the glycans on rrhGM-CSF are superior to the glycans on yrhGM-CSF in terms of in vivo stability.