Human IL-2 ELISA Kit

Principle of the Assay

This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for IL-4 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any IL-4 present is bound by the immobilized antibody. Following incubation unbound samples are removed during a wash step, and then a detection antibody specific for IL-4 is added to the wells and binds to the combination of capture antibody- IL-4 in sample. Following a wash to remove any unbound combination, and enzyme conjugate is added to the wells. Following incubation and wash steps a substrate is added. A coloured product is formed in proportion to the amount of IL-4 present in the sample. The reaction is terminated by addition of acid and absorbance is measured at 450nm. A standard curve is prepared from seven IL-4 standard dilutions and IL-4 sample concentration determined.

Target Information

Interleukin 4 (IL-4) is a pleiotropic cytokine produced primarily by activated T lymphocytes, mast cells and basophils. The sequence of human IL-4 cDNA predicts a 153 amino acid (aa) residue precursor protein containing a 24 aa residue signal peptide that is cleaved to form the mature protein. At the amino acid sequence level, mature human IL-4 is approximately 50% identical to mouse IL-4 and there is no species cross-reactivity between the two proteins. Human IL-4 also shares approximately 30% amino acid sequence identity to human IL-13 and the two cytokines exhibit overlapping biological activities. The gene for IL-4 has been mapped to human chromosome 5q, in close proximity to the genes for IL-3, IL-5, IL-13 and GM-CSF.

IL-4 has multiple immune response-modulating functions on a variety of cell types. It is an important regulator of isotype switching, inducing IgE production in B lymphocytes. It is an important modulator of the differentiation of precursor T helper cells to the TH2 subset that mediates humoral immunity and modulates antibody production. In addition, IL-4 has also been shown to have anti-tumor activity both in vivo and in vitro.

The biological effects of IL-4 are mediated by specific cell surface receptor complexes. One type of functional IL-4 receptor complex consists of the IL-4-binding subunit (IL-4 R) and a second chain, designated the common c chain because it has also been identified as a component of the receptor complexes for IL-2, IL-7, IL-9 and IL-15. A second type of functional IL-4 receptor complex, consisting of the IL-4 R and the more recently cloned IL-13 R, has also been proposed.

Although IL-4 R does not bind IL-13 directly, it has been shown to complex with the low-affinity IL-13 R to form the functional high-affinity receptor complex for IL-13. In addition to the membrane-bound form of IL-4 R, a naturally occurring soluble form of IL-4 R has been identified in human and mouse biological fluids and in mouse cell culture supernatants. Soluble IL-4 R has been shown to bind IL-4 with high affinity in solution.

GENE ID 3565

Materials Supplied

Kit Components 96 Wells Quantity/Size
Aluminium pouches with a Microwell Plate coated with monoclonal antibody to human IL-4 (8﹡12) 1 plate
Human IL-4 Standard lyophilized, 1000 pg/ml upon reconstitution 2 vials
Concentrated Biotin-Conjugate anti-human IL-4 monoclonal antibody 2 vials
Streptavidin-HRP solution 2 vials
Standard /sample Diluent 1 bottle
Biotin-Conjugate antibody Diluent 1 bottle
Streptavidin-HRP Diluent 1 bottle
Wash Buffer Concentrate 20x (PBS with 1% Tween-20) 1 bottle
Substrate Solution 1 vial
Stop Solution 1 vial
Adhesive Films 4 pieces
Product data sheet 1 copy


Storage Store at 2 - 8°C

Performance Characteristics

REPEATABILITY The coefficient of variation of both intra-assay and inter-assay were less than 10%.
SENSITIVITY The minimum detectable dose was 7pg/mL.
ASSAY RANGE 15.6 - 1000 pg/mL
SPECIFICITY This assay recognizes both natural and recombinant human IL-4. The factors listed below were prepared at 100ng/ml in Standard /sample Diluent and assayed for cross-reactivity and no significant cross-reactivity or interference was observed.
Factors assayed for cross-reactivity
Recombinant human G-CSF, GM-CSF, IL-1α, IL-1β, IL-2 sRα, IL-3, IL-5, IL-6, IL-7, IL-8, LIF, TGF-β1, TGF-β2, TNF-α, TNF-β, SCF, VEGF
Recombinant mouse IL-1α, IL-1β, IL-3, IL-5, IL-6, IL-7, IL-9, IL-10, IL-13, GM-CSF, LIF, MIP-1α, MIP-1β, TNF-α, SCF
Other proteins bovine FGF acidic, bovine FGF basic, human PDGF, porcine PDGF, human TGF-β1, porcine TGF-β1, rat TGF-β5