Interleukin-3 (IL-3) is produced by T cells, mast cells, and eosinophils (1). Target cells include hematopoietic progenitors, neutrophils, macrophages, mast cells, eosinophils, lymphoid, and erythroid cells (1). The IL-3 receptor is a heterodimer of the IL-3 specific α-chain and the common β-chain, βc, which is also used by GM-CSF and IL-5. (1). Binding of IL-3 can also involve substitution of the βc by a βIL-3-chain that appears to be specific for IL-3 (1,2). Binding of IL-3 to its cognate receptor(s) induces activation of Jak2, phosphorylation of multiple Stats (1,3,5,6), and the PI3K/Akt pathway (1). IL-3 may play an important role in the development of airway inflammation associated with asthma (3-5).

Endotoxin levels are less than 1 EU/ 1 µg hIL-3.

A greater than 95% purity was determined by SDS-PAGE.

Recombinant human Interleukin-3 was expressed in E.coli and is supplied in a lyophilized form.

The bioactivity of recombinant IL-3 was measured by human TF-1 erythroleukemic cells. The ED₅₀ is between 0.05-0.3 ng/mL.