Flt3 Ligand

Flt3-ligand (FMS related tyrosine kinase 3 ligand, flk-2 ligand) is involved in proliferation and differentiation of early hematopoietic cells. Flt3-ligand synergizes with other CSF’s and interleukins to induce proliferation of early hematopoietic cells but does not stimulate growth or differentiation alone. Flt3-ligand binds to cells expressing the tyrosine kinase receptor Flt3. Multiple isoforms of Flt3 ligand have been identified but the predominant biologically active isoform is a transmembrane protein which can be proteolytically cleaved to generate a biologically active soluble form.

Produced in the endosperm tissue of barley grain (Hordeum vulgare).

PBS pH 7.2, sterile filtered through 0.2 µm filter.

Greater than 95% by SDS-PAGE gel analysis.

Note: Always centrifuge the vial before opening. It is recommended to reconstitute the lyophilized protein in sterile buffered saline to a concentration of no less than 100 µg/ml. For long term storage of the reconstituted solution it is recommended to add a carrier protein (0.1% HSA or BSA).

The lyophilized protein, though stable at room temperature for few weeks, is best stored at -20°C. Reconstituted protein should be used immediately or stored in working aliquots at -20°C. Avoid repeated freeze-thaw cycles.

The bioactivity of ISOkine® recombinant human Flt-3 ligand was assayed by measuring its dose dependent effect on proliferation of AML5 cells.

The ED50 value for this ISOkine is < 0.3 ng/ml corresponding to specific activity > 3.3 x 10e6 U/mg.

We recommend that the optimal concentration for each specific application be determined by an initial dose response assay. Each batch of this ISOkine® growth factor is tested for bioactivity and verified to have comparable activity to a commercial source.

Endotoxin level is less than 0.005ng per µg of ISOkine® product (0.05EU/µg).

Purified ISOkine® product carries no pyrogenic or pro-inflammatory contaminants, as assayed with monocyte activation test using Human 10-plex Cytokine Assay measuring IL-6, TNF-alpha and IL-1beta induction. ** Ref. The Blood Bank, University Hospital of Iceland, Reykjavik, Iceland

Recombinant human Flt3-ligand contains 156 amino acids and a 16 a.a. Histidine-based tag for a total length of172 a.a. and has a predicted molecular mass of 19.9 kDa. As a result of glycosylation, the recombinant protein migrates as two bands with an apparent molecular mass of 20 and 22 kDa in SDS-PAGE.