What is the Difference Between G-CSF and GM-CSF

The main difference between G-CSF and GM-CSE is that G-CSF is a glycoprotein that stimulates the production of granulocytes and releases them into the bloodstream, whereas GM-CSF is a monomeric glycoprotein that macrophages, mast cells, T cells, natural killer cells, fibroblasts, and endothelial cells secrete as a cytokine. 

G-CSF and GM-CSF are two white blood cell stimulating factors that induce the proliferation of white blood cells. They stimulate the white blood cells to proliferate from stem cells. 

Key Areas Covered

1. What is G-CSF
– Definition, Features, Importance
2. What is GM-CSF
– Definition, Features, Importance
3. Similarities Between G-CSF and GM-CSF
– Outline of Common Features
4. Difference Between G-CSF and GM-CSF
– Comparison of Key Differences

Key Terms 

G-CSF, GM-CSF, Granulocyte-Colony Stimulating Factor, Granulocyte-Macrophage Colony-Stimulating Factor

What is G-CSF

G-CSF, or granulocyte-colony stimulating factor, is a type of hematopoietic growth factor that stimulates stem cells to produce granulocytes and release them into the bloodstream. It is a glycoprotein known as colony-stimulating factor 3 (CSF-3). Several body cells, including macrophages and other immune cells, and the endothelial cells produce G-CSF. It exists in two forms: 174 and 177 amino acids long chains. 174-Amino acids form is the most abundant and the more active form.

Figure 1: CSF 3

Furthermore, Function-wise, it is a colony-stimulating factor that serves as a cytokine and hormone. Several tissues in the body produce it. The primary function of G-CSF is to stimulate the proliferation, differentiation, function, and survival of neutrophil precursors and neutrophils. G-CSF receptors occur in the precursor cells of the bone marrow. In response to G-CSF, they initiate the proliferation and differentiation of granulocytes. Pharmaceutical analogs of G-CSF include filgrastim and lenograstim.

What is GM-CSF

GM-CSF or granulocyte-macrophage colony-stimulating factor is another type of hematopoietic growth factor secreted by macrophages, mast cells, T cells, natural killer cells, fibroblasts, and endothelial cells secreted as a cytokine. Another name for GM-CSF is colony-stimulating factor 2 (CSF 2). Pharmaceutical analogs of GM-CSF include sargramostim and molgramostim. In contrast to the G-CSF, the GM-CSF induces many types of cells to proliferate and differentiate, including macrophages and eosinophils. It stimulates the proliferation of granulocytes, including neutrophils, eosinophils, basophils, and monocytes. Here, monocytes exist in the bloodstream and migrate into the tissue to become macrophages and dendritic cells.

Figure 2: CSF 2

Moreover, GM-CSF is a part of the immune cascade in which the activation of the small number of macrophages causes a rapid increase in their number which is crucial in fighting infections. Additionally, GM-CSF affects mature cells, enhancing neutrophil migration and altering the receptors expressed on the cell surface.  

Similarities Between G-CSF and GM-CSF

• G-CSF and GM-CSF are two growth factors of white blood cells.
• They stimulate white blood cells to proliferate from stem cells.
• They are glycoproteins.

Difference Between G-CSF and GM-CSF

Definition

G-CSF refers to a type of growth factor that helps increase white blood cells called neutrophils, while GM-CSF refers to a growth factor that stimulates the production and release of white blood cells, especially granulocytes, macrophages, and cells that become platelets. 

Significance

G-CSF is a glycoprotein that produces granulocytes and releases them into the bloodstream by stimulating the bone marrow. In contrast, GM-CSF is a monomeric glycoprotein that macrophages, mast cells, T cells, natural killer cells, fibroblasts, and endothelial cells secrete as a cytokine. 

Cell Proliferation

G-CSF stimulates the proliferation of neutrophils, while GM-CSF stimulates the proliferation of other cell types, such as macrophages and eosinophils.

Other Names

Another name for G-CSF is colony-stimulating factor 3, while GM-CSF is also known as colony-stimulating factor 2.

Molecular Weight 

The molecular weight of G-CSF is 19 kDa, while the molecular weight of GM-CSF is 14 to 35 kDa.

Pharmaceutical Analogs 

Pharmaceutical analogs of G-CSF include filgrastim and lenograstim, while the pharmaceutical analogs of GM-CSF include sargramostim and molgramostim.

Conclusion

In brief, G-CSF and GM-CSF are two growth factors that stimulate the proliferation of white blood cells. They are glycoproteins. G-CSF stimulates the proliferation of granulocytes, especially neutrophils. It is also known as colony-stimulating factor 3. In comparison, GM-CSF stimulates the proliferation of other white blood cells, including macrophages and eosinophils. It is also known as colony-stimulating factor 2. Therefore, the main difference between G-CSF and GM-CSF is the type of cells proliferated by each growth factor. 

References:

1. Granulocyte colony stimulating factor (G-CSF). Cancer information | Cancer Research UK. (2022, February 15). https://www.cancerresearchuk.org/about-cancer/treatment/drugs/g-csf
2. Kurzrock R. Granulocyte-macrophage colony-stimulating factor. In: Kufe DW, Pollock RE, Weichselbaum RR, et al., editors. Holland-Frei Cancer Medicine. 6th edition. Hamilton (ON): BC Decker; 2003. 

Image Courtesy:

1. “GCSF Crystal Structure.rsh” By Ramin Herati – Own work (Public Domain) via Commons Wikimedia
2. “GMCSF Crystal Structure.rsh.” By Ramin Herati – Own Work (Public Domain) via Commons Wikimedia