GM-CSF was first cloned in 1985, and soon afterwards three potential drug products were being made using recombinant DNA technology: molgramostim was made in "Escherichia coli" and is not glycosylated, sargramostim was made in yeast, has a leucine instead of proline at position 23 and is somewhat glycosylated, and regramostim was made in Chinese hamster ovary cells (CHO) and has more glycosylation than sargramostim. The amount of glycosylation affects how the body interacts with the drug and how the drug interacts with the body.