What is interleukin 12?

Signaling molecule. Interleukin-12 (il-12) is known as a cytokine, which are small cell-signaling protein molecules that are secreted by numerous cells and are used extensively in intercellular communication. Il-12 is secreted by certain types of immune cells (such as dendritic cells) to regulate other members of the immune cells (for example, natural killer (nk) cells).