Intended use

This immunoassay kit allows for the specific measurement of human Interleukin 12, IL-12/P40 concentrations in tissue homogenates, cell culture supernates, serum, and plasma and other relevant liquid.

 

Introduction

Interleukin 12 (IL-12) is an interleukin that is naturally produced by macrophages and human B-lymphoblastoid cells (NC-37) in response to antigenic stimulation. IL-12 is composed of a bundle of four alpha helices. It is a heterodimeric cytokine encoded by two separate genes, IL-12A (p35) and IL-12B (p40). The active heterodimer, and a homodimer of p40 are formed following protein synthesis.

IL-12 is involved in the differentiation of naive T cells into Th1 cells, which is important in resistance against pathogens. It is known as a T cell stimulating factor, which can stimulate the growth and function of T cells. It stimulates the production of interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) from T and natural killer (NK) cells, and reduces IL-4 mediated suppression of IFN-γ. T cells which produce IL-12 have a coreceptor, CD30, which is associated with IL-12 activity.

IL-12 plays an important role in the activities of natural killer cells and T lymphocytes. IL-12 mediates enhancement of the cytotoxic activity of NK cells and CD8+ cytotoxic T lymphocytes. There also seems to be a link between IL-2 and the signal transduction of IL-12 in NK cells. IL-2 stimulates the expression of two IL-12 receptors, IL-12R-β1 and IL-12R-β2, maintaining the expression of a critical protein involved in IL-12 signaling in NK cells. Enhanced functional response is demonstrated by IFN-γ production and killing of target cells.

IL-12 also has anti-angiogenic activity, which means it can block the formation of new blood vessels. It does this by increasing production of interferon gamma, which in turn increases the production of a chemokine called inducible protein-10 (IP-10 or CXCL10). IP-10 then mediates this anti-angiogenic effect. Because of its ability to induce immune responses and its anti-angiogenic activity, there has been an interest in testing IL-12 as a possible anti-cancer drug. There is a link that may be useful in treatment between IL-12 and the diseases psoriasis and inflammatory bowel disease.

 

Test principle

This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for IL-12/P40 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any IL-12/P40 present is bound by the immobilized antibody. An biotinylated polyclonal antibody specific for IL-12/P40 is added to the wells. Following a wash to remove any unbound reagent, an enzyme complex is added to the wells.After incubation and washing ,a substrate solution is added to the wells and color develops in proportion to the amount of IL-12/P40 bound in the initial step. The color development is stopped and the intensity of the color is measured.