Hu Recom IL-4, 20 µg

A lyophilized recombinant human cytokine from STEMCELL Technologies, Interleukin-4 (IL-4) — also known as B cell stimulating factor, BCDF, BCGF, and BSF31 — is produced in E. coli and supplied as a sterile-filtered powder containing 0.1% trifluoroacetic acid. The protein has a predicted molecular mass of 15.1 kDa and is referenced under accession number P05112. It is provided for cell culture applications.

Biological activity is determined by a cell proliferation assay using TF-1 cells, with the EC50 defined as ≤ 0.25 ng/mL and a representative range of 0.16 - 0.24 ng/mL after 72 hours of culture. Specific activity is approximately 1.4 x 10^4 IU/µg, calibrated against the human recombinant IL-4 WHO International Standard (NIBSC code: 88/656). Purity is ≥ 95%, and endotoxin is ≤ 1 EU/μg protein as measured by kinetic LAL analysis. Human IL-4 does not cross-react with mouse cells.

IL-4 drives immunoglobulin class switching in B cells, mast cell hyperplasia, mucus production, and the differentiation of naïve T cells into T helper type 2 (Th2) cells. According to the manufacturer's Safety Data Sheet, the product is not classified as hazardous under GHS and is not WHMIS controlled.