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


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 larger 40-kDa subunit (p40) is a member of the cytokine receptor family whereas the smaller 35-kDa subunit (p35) has been found to be related to IL-6 and GCSF.

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 of IL-12 to produce a composite cytokine IL-23, whereas p19 subunit alone has no biological activity.

The human 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. For both human and mouse p35 and p40, the separate functions of the mature molecules can be attributed to p35 and p40. 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 human interleukin-12 p40.
  • Sample/Standard Dilution Buffer.
  • Biotinylated-labelled IL-12 p40 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 human IL-12 p40 ELISA kit was approximately 18.75 pg/ml. The dynamic range for this assay is 31.2 – 2,000 pg/ml.


– Interleukin-12 P40 (IL-12 P40): ELISA
– 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. Making many from few: IL-12p40 as a model for the combinatorial assembly of heterodimeric cytokines. Cytokine. (2015) 76 (1): 53-7. Review. Abdi K. and Singh N.J.
  3. The regulation and biological activity of interleukin 12. Leuk Lymphoma. (1998) 29 (5-6): 427-38. Review. Lee S.M., et al.
  4. 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.
  5. IL-12: the role of p40 versus p75. Scand J Immunol. (2002) 56 (1): 1-11. Review. Abdi K.


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



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