Hu Recom IL-4, 500 µg

A research-grade human cytokine preparation from STEMCELL Technologies, expressed in E. coli and supplied as a lyophilized solid from a sterile-filtered aqueous solution containing 0.1% trifluoroacetic acid. The protein has a predicted molecular mass of 15.1 kDa, a purity of ≥ 95%, and endotoxin levels of ≤ 1 EU/μg protein as determined by kinetic LAL analysis.

Interleukin-4 (IL-4) is a central mediator of type 2 immune responses, acting through a heterodimeric receptor composed of IL-4Rα and the common gamma chain. Receptor engagement activates JAK1/3 and recruits STAT6 and IRS1/2. IL-4 drives immunoglobulin class switching in B cells (to IgE and IgG4), mast cell hyperplasia, mucus production, and the differentiation of naïve T cells into T helper type 2 (Th2) cells, which in turn produce IL-4, IL-5, IL-10, and IL-13. IL-4 is also produced by CD4+ NK T cells, γ/δ T cells, activated basophils, eosinophils, and mast cells. Human IL-4 does not cross-react with mouse cells.

Biological activity is determined by a cell proliferation assay using TF-1 cells, measured after 72 hours with a fluorometric method. The EC50 is ≤ 0.25 ng/mL, with a representative range of 0.16 – 0.24 ng/mL. The specific activity is approximately 1.4 × 10^4 IU/µg, calibrated against the human recombinant IL-4 WHO International Standard (NIBSC code: 88/656). The product is for research use only, is not classified as a hazardous substance or mixture according to GHS, is stable under normal conditions, and is not regulated for transport by DOT, TDG, IATA, or IMDG. Recommended storage is at -20°C to -80°C, with stability of 12 months from date of receipt when stored as supplied.