Interleukin-12: a proinflammatory cytokine with immunoregulatory functions

Interleukin-12 molecule : structure and biological activities Interleukin-12 (IL12) is a heterodimeric cytokine, composed of a heavy chain of 40 kDa and a light chain of 35 kDa, originally described with the name of natural killer stimulatory factor (NKSF) as a product of EBV-transformed human B-lymphoblastoid cell lines (Kobayashi et al., 1989).A cytotoxic lymphocyte maturation factor (CLMF) was later described, also as a product of B-cell lines (Stem et al., 1990), and upon cloning of the two genes coding both NKSF and CLMF, the two cytokines were found to be identical (Wolf et al., 1991) and the name of IL12 is now commonly used.