IL-3 is produced mainly by T cells following cell activation by antigens and mitogens, but also by keratinocytes, natural killer cells, mast cells, endothelial cells, and monocytes. The analysis of bacterial-derived recombinant IL-3 shows that glycosylation is not required for the activity of IL-3. IL-3 sequences are evolutionarily less well conserved. Human and murine IL-3 show approximately 29 % homology at the protein level while murine and rat IL-3 show approximately 54% homology. IL-3-alpha and IL-3-beta are two isoforms of rat IL-3. IL-3 receptors are expressed on macrophages, mast cells, eosinophils, megakaryocytes, basophils, bone marrow progenitor cells, and various myeloid leukemia cells. IL-3/receptor complexes have a Kdis of 10-9 - 10-10 M. Binding of IL-3 to its receptor causes specific phosphorylation of a 150 kDa membrane glycoprotein.
<1.0 EU/μg of recombinant protein as determined by the LAL method.
Biological Activity Comment
The ED(50) was determined by the dose-dependent proliferation of human TF-1 cells was found less than 0.1 ng/mL.
Weight
15.0 kDa
Description
A quick spin of the vial followed by reconstitution in distilled water to a concentration not less than 0.1 mg/mL. This solution can then be diluted into other buffers.
Format
Lyophilized PowderRecombinant Interleukin-3 was lyophilized from a 0.2 μm filtered PBS solution pH 7.0.
Purity
>95% as determined by SDS-PAGE
Storage
The lyophilized protein is stable for at least one year from date of receipt at -70°C. Upon reconstitution, this cytokine can be stored in working aliquots at 2° - 8°C for one month, or at -20°C for six months, with a carrier protein without detectable loss of activity. Avoid repeated freeze/thaw cycles.