Interleukin-12 (IL12; formerly NKSF, for natural killer cell stimulatory factor, or CLMF, for cytotoxic lymphocyte maturation factor) is a novel cytokine cloned from B-cell lines. IL-12 is a heterodimeric molecule composed of p35 and p40 subunits.1 The larger 40-kDa subunit (p40) is a member of the cytokine receptor family, and the smaller 35-kDa subunit (p35) is related to IL6 and GCSF.2 Both IL-12 p40(-/-) and p35(-/-) mice fail to produce IL-12 p70 heterodimer.3 Interleukin (IL)-12 has been cloned on the basis of its ability to activate natural killer (NK) cells and promote the development of cytolytic T cells. With further understanding of its activities, IL-12 has emerged as an important cytokine, affecting both immune and hematologic functions. It has been shown to be necessary for the T cell independent induction of interferon (IFN)-gamma, critical for the initial suppression of bacterial and parasitic infection; for the development of a Th1 response, critical for effective host defense against intracellular pathogens; and for the activation of differentiated T lymphocytes of both CD4+ and CD8+ phenotype.4 The subunits map to different chromosomes: p40 (IL12B) to 5q31-q33 and p35 (IL12A) to 3p12-3q13.2.2 The standard product used in this kit is recombinant human IL-12(p40), which is a 40 KDa glycoprotein consisting of 306 amino acids.

ScienCell's human IL-12(p40) ELISA Kit is based on standard sandwich enzyme-linked immune-sorbent assay technology. Human IL-12(p40)-specific monoclonal antibodies are pre-coated onto 8 x 12 strips. The human specific detection polyclonal antibodies are biotinylated. The test samples and biotinylated detection antibodies are subsequently added to the wells and then washed with PBS or TBS buffer. Avidin-Biotin-Peroxidase Complex is added and unbound conjugates are washed away with PBS or TBS buffer. HRP substrate TMB is used to visualize HRP enzymatic reaction. TMB is catalyzed by HRP to produce a blue color product that changes into yellow after adding acidic stop solution. The intensity of yellow is proportional to the amount of human IL-12(p40) in the sample that is captured in the strips.