IL-3 (Interleukin-3) is a cytokine that regulates haemopoiesis, the formation of blood cells in the body. IL-3, also called multi-CSF (multi-lineage colony stimulating factor), is produced by T cells and mast cells, after activation with mitogens or antigens. The molecular weight of IL-3, a protein of 140 amino acids, ranges from 14 to 36 kDa. It stimulates eosinophils and B cell differentiation while it inhibits LAK (Lymphokine-Activated Killer) cell activity. IL-3 shares several biological activities with GM-CSF. IL-3 is capable of inducing the growth and differentiation of multi-potential haematopoetic stem cells, neutrophils, eosinophils, megakaryocytes, macrophages, lymphoid and erythroid cells (Ref.1). IL-3R (IL-3 receptor) is composed of two polypeptide chains, an Alpha subunit of 60-70kDa and a Beta subunit of 130-140kDa. Both subunits contain the extracellular conserved motifs found in the cytokine receptor superfamily. The common Beta -chain receptor subunit (c), which is shared among the receptors for IL-3, IL-5 and granulocyte/macrophage colony-stimulating factor, is essential for signal transduction in cell proliferation and differentiation induced by these cytokines, and plays a major role in recruiting intracellular signaling molecules such as JAK2 (Janus Kinase2) tyrosine kinase and STAT5 (Signal Transducers And Activators Of Transcription) (Ref.2).
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1.IL-3 induces B7.2 (CD86) expression and costimulatory activity in human eosinophils.
Celestin J, Rotschke O, Falk K, Ramesh N, Jabara H, Strominger J, Geha RS. J Immunol. 2001 Dec 1;167(11):6097-104. 2.Inhibition of GM-CSF/IL-3/IL-5 signaling by antisense oligodeoxynucleotides targeting the common beta chain of their receptors. Allam M, Renzi PM. Antisense Nucleic Acid Drug Dev. 2001 Oct;11(5):289-300. 3.IL-3 signaling and the role of Src kinases, JAKs and STATs: a covert liaison unveiled. Reddy EP, Korapati A, Chaturvedi P, Rane S. Oncogene. 2000 May 15;19(21):2532-47. 4.Activation of the interleukin-3 gene by chromosome translocation in acute lymphocytic leukemia with eosinophilia. Meeker, T. C.; Hardy, D.; Willman, C.; Hogan, T.; Abrams, J. Blood 76: 285-289, 1990.
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