Mini Sample Rat IL-4 (Interleukin 4) ELISA Kit (E-MSEL-R0007)

Interleukin 4 (IL-4) is a pleiotropic cytokine that has multiple immune response-modulatingactivities on a variety of cell types . IL-4 is a B cell activation/differentiation factor thatregulates Ig isotype switching, particularly IgG1 and IgE. It suppresses the development ofIFN-γ-producing CD4+ T cells and regulates the differentiation of naïve precursor T helper cellsto the Th2 subset that mediates allergic and humoral immune response. Together withTNF-α, IL-4 synergistically induces the expression of VCAM-1 on vascular endothelial andsmooth muscle cells, resulting in the selective recruitment of eosinophils and lymphocytes tothe site of inflammation. IL-4 downregulates the production of inflammatory mediatorssuch as IL-1, TNF-α, and PGE2 in monocytes. IL-4 has also been shown to have anti-tumoractivity both in vivo and in vitro. Cells that have been shown to secrete IL-4 include basophils, CD8+ T cells, CD4+ memory and naïve Th2 cells, mast cell, eosinophils, andvirally activated dendritic cells.The cDNA sequence of rat IL-4 predicts a 147 amino acid (aa) residue precursor proteincontaining a 24 aa residue signal peptide that is cleaved to generate the 123 aa residue matureprotein containing four potential N-linked glycosylation sites and seven cysteine residues. Six of the seven cysteine residues are involved in the formation of three intramoleculardisulfide linkages that are essential for activity. In humans, an alternately spliced truncatedIL-4 variant lacking the sequence encoded by the second of the four exons has been described. Recombinant human truncated IL-4 has been shown to have antagonistic effects onIL-4 activities in human monocytes and B cells. It is not known if truncated IL-4 is producednaturally. Mature rat IL-4 shares 60% and 44% amino acid sequence similarity with mouseand human IL-4, respectively.Functional IL-4 receptor complexes are present in many cell types including astrocytes,fibroblasts, hepatocytes, hematopoietic, epithelial, endothelial, and vascular smooth musclecells. One type of IL-4 receptor complex consists of a heterodimeric complex between the140 kDa IL-4 Rα chain that binds IL-4 with high affinity, and the gamma common chain (γc)which is required for IL-4 signaling. In non-hematopoietic cells where γc is absent, IL-4 Rαcan also heterodimerize with the 65 kDa IL-13 Rα1 chain to transduce IL-4 signals. In somecells, IL-4 signaling as a result of IL-4 Rα homodimerization has also been reported. Inaddition to the membrane bound form of IL-4 Rα, a naturally occurring soluble form of IL-4 Rαhas been identified in mouse biological fluids and in mouse cell culture supernatants.