IL-12 P40 ELISA Kit (Interleukin-12 p40)


Human IL-12 p40 ELISA kit is designed for measuring in vitro quantitative amounts of interleukin-12 p40 (IL-12 p40) present in human biological fluids, serum, tissue homogenates and plasma (EDTA, heparin, citrate). This assay has a minimum detection limit of 18.75 pg/ml.


Interleukin 12 (IL-12) which is also called by the following names cytotoxic lymphocyte maturation factor (CLMF) and natural killer cell stimulatory factor (NKSF), is a 75kDa glycoprotein heterodimer that is made up of two unequal, genetically-unrelated subunits (p35 and p40 subunits). The p40 subunit is secreted in excess of IL-12p35 and has the ability to associate with p19 (IL-23p19 or IL-23A) in order to form IL-23. There is also sequence similarity shared between the p19 subunit and IL-6 subfamily members including the p35 subunit of IL-12. However, it can only become biologically active when it combines with the p40 subunit to produce a composite cytokine IL-23, whereas P19 subunit alone has no biological activity.

IL-12 p40 subunit has total molecular weight of 34.7 kDa and is made up of 306 amino acid residues in length. There are potentially four N-linked glycosylation sites and 10 cysteine residues. In murine p40 there is approx. 70% sequence homology to human and it contains 313 amino acid residues possessing 11 conserved cysteines and three N-linked glycosylation sites. The preliminary evidence is indicating that p40 is involved in receptor binding whereas P35 is important in signal transduction.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • One 96-Well Plate: Pre-coated with anti-human IL-12 p40 antibody.
  • Standards: Concentrations 0, 31.25, 62.5, 125, 250, 500, 1000, 2000 pg/ml, made up from lyophilized recombinant.
  • Sample/Standard Dilution Buffer.
  • Biotinylated-Labelled-Antibody.
  • Antibody Dilution Buffer.
  • HRP-Streptavidin Conjugate (SABC).
  • SABC Dilution Buffer.
  • TMB Substrate.
  • Wash Buffer (25x).
  • Plate Sealer.
  • Product Instructions.


The minimum detection sensitivity level of interleukin-12 p40 (IL-12 p40) using this IL-12 p40 ELISA kit was approximately 18.75 pg/ml. The dynamic range for this assay is 31.2 – 2,000 pg/ml.


– Specificity: Highly specific for IL-12 p40, no cross reactivity or interference between IL-12 p40 and analogues was detected.
– Recovery: Serum (86 – 104%), EDTA Plasma (94 – 103%), Heparin Plasma (86 – 100%).
– Linearity: Serum (86 – 101%), EDTA Plasma (83 – 100%), Heparin Plasma (82 – 99%).
– Precison Intra-Assay: CV < 8%.
– Precison Inter-Assay: CV < 10%.
– Stability: Less than 10%.


  1. IL-12p40: an inherently agonistic cytokine. Trends Immunol. (2007) 28 (1): 33-8. Review. Cooper A.M. and Khader S.A.
  2. The regulation and biological activity of interleukin 12. Leuk Lymphoma. (1998) 29 (5-6): 427-38. Review. Lee S.M., et al.
  3. Does p40-targeted therapy represent a significant evolution in the management of plaque psoriasis? J Eur Acad Dermatol Venereol. (2012) 26 Suppl 5: 2-8. Review. Griffiths C.E. and Girolomoni G.
  4. IL-12: the role of p40 versus p75. Scand J Immunol. (2002) 56 (1): 1-11. Review. Abdi K.


  • Full Name: IL-12 P40 ELISA Kit (Interleukin-12 p40)
  • Reactivity: Human
  • Sample Type: Tissue Homogenates, Serum, Plasma, Biological Fluids
  • Sensitivity: 18.75 pg/ml


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