CellaQuant™ Rat IL-4 (Interleukin 4) ELISA Kit (CQR007)

This ELISA kit uses the Sandwich-ELISA principle. The micro ELISA plate provided in this kit has been pre-coated with an antibody specific to Rat IL-4. Samples (or Standards & Quality Control Material) are added to the micro ELISA plate wells and combined with the specific antibody. Then a biotinylated detection antibody specific for Rat IL-4 and Avidin-Horseradish Peroxidase (HRP) conjugate are added successively to each micro plate well and incubated. Free components are washed away. The substrate solution is added to each well. Only those wells that contain Rat IL-4, biotinylated detection antibody and Avidin-HRP conjugate will appear blue in color. The enzyme-substrate reaction is terminated by the addition of stop solution and the color turns yellow. The optical density (OD) is measured spectrophotometrically at a wavelength of 450±2 nm. The OD value is proportional to the concentration of Rat IL-4. You can calculate the concentration of Rat IL-4 in the samples by comparing the OD of the samples to the standard curve.

Human Interleukin-4 (IL-4) is a pleiotropic cytokine primarily produced by Th2-polarized CD4+ T cells, mast cells, basophils, and eosinophils. It is the master regulator of type 2 immunity, driving the differentiation of naïve CD4+ T cells into Th2 cells, thereby creating a self-amplifying loop that secretes IL-4, IL-5, and IL-13 to promote humoral immunity while suppressing Th1-mediated cellular responses. For B cells, IL-4 acts as a co-stimulator for proliferation and directs immunoglobulin class switching to IgE and IgG4. It also upregulates MHC class II molecules on B cells and enhances expression of the low-affinity IgE receptor (CD23) on lymphocytes and monocytes. Furthermore, IL-4 primes and recruits mast cells, basophils, and eosinophils, stimulating epithelial cell proliferation and activating macrophages by increasing IL31RA expression. It induces autophagy in dendritic cells via mTORC1 inhibition and RUFY4 induction. IL-4 signals through two receptor complexes: the type I receptor (IL-4Rα and common γ-chain) on hematopoietic cells, and the type II receptor (IL-4Rα and IL-13Rα1) on non-hematopoietic cells, which also mediates IL-13 signaling. Its dominant role in promoting IgE production and allergic inflammation makes it a critical therapeutic target in conditions like asthma and atopic dermatitis.