blood interleukin amount blood interleukin-12 amount circulating natural killer cell stimulatory factor level circulating interleukin-12 p70 level Trait.ontology circulating IL-12 level The proportion, quantity, or volume in whole blood, serum, or plasma of a heterodimeric cytokine that plays a role in innate and adaptive immune responses; it is produced by dendritic cells, macrophages and a variety of other immune cells and plays a role in the stimulation of interferon-gamma production by T-cells and natural killer cells. Interleukin-12 is a 70 kDa protein that is composed of covalently linked 40 kDa (IL-12b) and 35 kDa (IL-12a) subunits. The 40 kDa subunit (IL-12b) also is a component of interleukin-23 together with the IL-23a ( 19kDa) chain. EFO:0004753 circulating cytotoxic lymphocyte maturation factor level circulating interleukin-12 level VT:0008616 circulating IL12 level circulating IL-12 p70 level