IL-4

IL-4 (Interleukin 4, B cell stimulatory factor) is a pleiotropic cytokine produced by activated T cells, mast cells and basophils. IL-4 has many different functions including promoting proliferation and differentiation of immunologically competent cells. One of its main functions is regulating differentiation of naive CD4+ T cells into helper Th2 cells, the other main function is regulating B cells IgE and IgG1 production. Human IL-4 shows 50% homology with mouse IL-4, but its activities are species-specific and human IL-4 shows no activity on murine and rat cells.

This recombinant human IL-4 consists of 146 amino acid residues. In addition, it contains a 10 aa tag at the Recombinant human IL-4 contains 130 amino acids and a 16 a.a. Histidine-based tag for a total length of 146 a.a. and has a predicted molecular mass of 17.2 kDa. Due to glycosylation, the recombinant protein migrates as a smeary band with an apparent molecular mass of 23 kDa in SDS-PAGE.

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

The bioactivity of ISOkine® recombinant human IL-4 was assayed by measuring its dose dependent effect on proliferation of TF-1 cells.

The ED50 value for this effect is < 0.4 ng/ml, corresponding to a specific activity > 2.5 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 factors 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 < 0.01 EU per μg of ISOkine® product (< 0.01 EU/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 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.