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Interleukin-12 Subunit p40 (IL-12p40)

Ultrasensitive Immunoassay


Rules-Based Medicine’s internally developed and manufactured ultrasensitive immunoassay to interleuking-12 subunit p40 (IL-12p40) based on the Simoa® bead technology can accurately quantitate sub-pg/mL levels of IL-12p40 in human plasma and serum. The Simoa IL-12p40 assay is a valuable clinical research tool for pharmacodynamic analysis of autoimmune, inflammatory, and infectious diseases.

Interleukin-12 subunit p40 (IL-12p40) is also known as IL-12B, natural killer cell stimulatory factor 2, and cytotoxic lymphocyte maturation factor p40. IL-12p40 is a subunit of IL-12p70 and IL-23. It can exist as a monomer or homodimer (IL-12p80) and can function as a negative feedback loop by competitively binding to the IL-12 receptor. Produced primarily by macrophages, neutrophils, microglia, and dendritic cells, IL-12p40 induces and activates T helper-1 cells in cooperation with IL-12p70. It also promotes the induction and activation of T helper-17 cells in cooperation with IL-23. IL-12p40 is a chemoattractant for macrophages and induces dendritic cells stimulated by bacteria to migrate.

IL-12p40 is associated with inflammatory responses including silicosis, graft rejection, asthma, and juvenile idiopathic arthritis. Serum levels of IL-12p40 are significantly higher in patients with active tuberculosis and latent tuberculosis compared to patients without tuberculosis. IL-12p80 have been detected in bronchoalveolar lavage of asthmatic patients. Blocking IL-12p40 has been shown to be efficacious in treating Inflammatory Bowel Diseases such as Crohn’s Disease and ulcerative colitis by repressing T helper-1 cell type immune responses. IL-12p40 is an attractive target since it can affect activities of both IL-12p70 and IL-23.


Swiss-Prot Accession Number: P29460

Alternate names for this biomarker include:

Cytotoxic lymphocyte maturation factor 40 kDa subunit, CLMF p40, NK cell stimulatory factor chain 2, NKSF2

Simoa™ Services
Biomarker LLOQ*
(Serum and Plasma)
(Undiluted Samples)
Volume Required
Serum or plasma Other fluids**
Interleukin-12 Subunit p40 (IL-12p40) 7.3 pg/mL 0.730 pg/mL 50 µL 150 µL

* Lower limit of quantitation (LLOQ) represents the lowest amount of an analyte that can be quantitatively determined with acceptable precision. LLOQ is determined by performing 2-fold serial dilutions of Standard to be tested in triplicate over three runs. The percent coefficient of variation (CV) is calculated for each of the dilution replicates, and the LLOQ is determined as the concentration at which the CV is 30%.

** Cerebrospinal fluid, urine, tissue culture supernatants,  bronchoalveolar lavage, synovial fluid, tissue extracts, tears, skin washings, etc.

All assay services are performed in our CLIA-certified laboratory.
Intended for Research Use Only.