Interleukin 3 (IL-3) is a protein that in humans is encoded by the IL3 gene localized on chromosome 5q31.1. Sometimes also called colony-stimulating factor, multi-CSF, mast cell growth factor, MULTI-CSF, MCGF; MGC79398, MGC79399: after removal of the signal peptide sequence, the mature protein contains 133 amino acids in its polypeptide chain. IL-3 is produced as a monomer by activated T cells, monocytes/macrophages and stroma cells. The major function of IL-3 cytokine is to regulate the concentrations of various blood-cell types. It induces proliferation and differentiation in both early pluripotent stem cells and committed progenitors. It also has many more specific effects like the regeneration of platelets and potentially aids in early antibody isotype switching.
Function
Interleukin 3 is an interleukin, a type of biological signal (cytokine) that can improve the body's natural response to disease as part of the immune system. This high affinity receptor contains α and β subunits. IL-3 shares the β subunit with IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF). This β subunit sharing explains the biological functional similarities of different hematopoietic growth factors.
IL-3 receptors can be found on a variety of cell types including many immature myelomonocytic cells in the hemopoietic system such as hemopoietic progenitor cells, as well as certain myeloid progenitors, basophils, and eosinophils.
Disease
IL-3 is produced by T cells only after stimulation with antigens or other specific impulses.
However, it was observed that IL-3 is present in the myelomonocytic leukaemia cell line WEHI-3B. It is thought that this genetic change is the key in development of this leukemia type. Post-chemotherapy, IL-3 application reduces chemotherapy delays and promotes regeneration of granulocytes and platelets. However, only IL-3 treatment in bone marrow failure disorders such as myelodysplastic syndrome (MDS) and aplastic anemia (AA) was disappointing.
Other studies showed that IL-3 could be a future perspective therapeutic agent in lymphohematopoietic disorders and solid cancers.
Interactions
Interleukin 3 has been shown to interact with IL3RA.
See also
- Interleukin