LIF - mouse

LIF (leukemia inhibitory factor, myeloid leukemia inhibitory factor) a pleiotropic lymphoid factor was initially described as a factor that inhibits the proliferation of myeloid leukemia cells and induces their differentiation into macrophages. Other activities of LIF include inhibition of adipogenesis, cholinergic neuron differentiation and bone metabolism . Human and mouse LIF share 78% homology and activities of LIF are not species specific. Human LIF is active on mouse cells, but murine LIF is not active on human cells. Embryonic stem cell (ESC)–qualified.

Recombinant mouse LIF contains 188 amino acids and a 10 a.a. histidine based tag for a total length of 199 a.a. and has a predicted molecular mass of 21.2 kDa. As a result of glycosylation, the recombinant protein migrates with an apparent molecular mass of 28 30 kDa in SDS PAGE.

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

The bioactivity of ISOkine® recombinant murine LIF was determined by its ability to induce differentiation of murine M1 myeloid leukemia cells where 50 U is defined as the amount of mLIF required to induce differentiation of 50% of M1 cells.

The ED50 value for this effect is <0.4 ng/ml corresponding to specific activity of >2.5 x 10e6 U/mg.

The ISOkine® mLIF has been validated in standard mESC based gene targeting for generation of knock out mice.

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

Greater than 95% by SDS-PAGE gel analysis.

Endotoxin level is <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 (MAT Assay) using Human 10-plex Cytokine Assay measuring IL-6, TNF-alpha and IL-1 beta induction.

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.

Highly stable as supplied for a maximum of 5 years and a minimum of 12 months from date of receipt (check expiration date specific for each lot# on Certificate of Analysis).

Note: Always centrifuge the vial before opening. It is recommended to reconstitute the lyophilized protein in sterile phosphate 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).

PBS pH 7.2, sterile filtered through 0.2 µm filter.