IL-12 is produced by dendritic cells, macrophages, and human B-lymphoblastoid cells in response to antigenic stimulation. It is a 70 kD heterodimeric glycoprotein comprised of disulfide-bonded 35 kD and 40 kD subunits. IL-12 is involved in the differentiation of naïve T cells into Th0 cells which will further develop into either Th1 cells or Th2 cells. IL-12 plays an important role in the activities of natural killer cells and T lymphocytes. It mediates enhancement of the cytotoxic activity of NK cells and CD8+ cytotoxic T lymphocytes. IL-12 is linked with autoimmunity due to its key role in induction of Th1 immune responses.

Cytokine detection

IL-12, IL-23 and IL-35 share common subunits, utilizing combinations of p40, p19 and p35 proteins. Caution must be used when selecting antibodies and assays when specific identification, measurement, as well as activation state discrimination, is required.

1. Active IL-12 consists of two subunits: p40 + p35.
2. p40 can also exist as a monomer (IL-12 p40) or a homodimer (IL-12 p80).
3. Besides contributing to IL-12, p40 is also found in IL-23, a heterodimer of p40 and p19.
4. Similarly, p35 not only contributes to IL-12, but is also found in the heterodimer IL-35 (p35 and EBI3).

Note that assays using antibodies specific for the p40 subunit will be unable to discriminate between the active IL-12, monomeric p40, dimeric p40, and IL-23; likewise, assays using p35 detection alone will pick up both IL-12 (heterodimer) and IL-35.

BioLegend ELISA assays

BioLegend’s LEGEND MAX™ Human IL-12 (p70) ELISA Kit is a sandwich Enzyme-Linked Immunosorbent Assay (ELISA), in which, a Human IL-12 (p70) specific monoclonal antibody is pre-coated on a 96-well strip-well plate. BioLegend’s LEGEND MAX™ Human IL-12 (p70) ELISA Kit is specifically designed for the accurate quantitation of Human IL-12 (p70) from cell culture supernatant, serum, plasma or other bodily fluids. It is ready-to-use, accurate, and sensitive.