Interleukin 12 (IL-12), also known as natural killer cell stimulatory factor (NKSF) or cytotoxic lymphocyte maturation factor (CLMF), is a heterodimeric pleiotropic cytokine made up of a 40 kDa (p40) subunit and a 35 kDa (p35) subunit. The IL-12 p40 subunit is shared by IL-23, another heterodimeric cytokine that has biological activities similar to, as well as distinct from, IL-12. IL-12 is produced by macrophages and B cells and has been shown to have multiple effects on T cells and natural killer (NK) cells. While mouse IL-12 is active on both human and mouse cells, human IL-12 is not active on mouse cells.

Assay #1: ED50 < 0.1 ng/ml, determined by the stimulation of IFN-gamma production by murine splenocytes co-stimulated with IL-18.

Assay #2: ED50 is ≤ 0.1 ng/ml, etermined by its ability to stimulate the proliferation of 2D6 cells.

Assay #1: > 1 x 107 units/mg
Assay #2: > 1 x 107 units/mg