Cell Culture 

Applications
Human IL-12 can be used for a variety of applications, including:

• In vitro differentiation of naive CD4+ T cells towards TH 1 cells.
• In vitro proliferation and stimulation of cytotoxic activity of NK cells and T cells.

Background information
Interleukin 12 (IL-12) is a heterodimeric proinflammatory cytokine and a modulator of cell-mediated immunity, which is mainly produced by macrophages, dendritic cells, and B cells. IL-12 stimulates the production and secretion of several cytokines, in particular IFN-γ, by NK cells and T cells, induces proliferation, and enhances the cytotoxic activity within these cell populations. Another important activity of IL-12, acting together with IFN-γ and IL-2, is to drive T helper cell responses toward the TH 1 rather than the TH 2 phenotype. Moreover, IL-12 is also important in resistance to viral disease and has significant antitumor activity. It has been shown that single chain fusion proteins of naturally occurring heterodimeric cytokines such as IL-12 or IL-23 are bioactive in vitro and in vivo.

Quality description
Premium-grade cytokines offer the convenience of high and well-defined biological activities and allow exact unit dosing for demanding applications. The biological activity is determined after lyophilization and reconstitution, and normalized to WHO/NIBSC standards whenever available. In general, endotoxin levels are <0.01 ng/μg (<0.1 EU/μg), and purities are >97%. Lot-specific certificates of analysis are available on request.

Biological activity
Induction of IFN-γ secretion by human T cells (NIBSC 95/544)
premium grade: ≥ 3×10⁶ U/mg