Animal-free Recombinant Human G-CSF is expressed in human 293 cells as a monomeric glycoprotein with an apparent molecular mass of 21 to 25 kDa. This molecular mass is due to glycosylation, which is absent when this cytokine is expressed in E. coli. Glycosylation contributes to stability in cell growth media and other applications. It stimulates the growth of progenitor cells to neutrophils and enhances the functional activities of the mature end-cell. This cytokine is produced in a serum-free, chemically defined media.