IL-12 [JJ07]

Interleukin-12 The interleukins (ILs) are a broad family of well characterized cytokines, primarily of hematopoietic cell origin. As new cytokines are molecularly characterized, they are assigned an IL number to maintain a standard nomenclature. ILs are secreted by immune cells (mainly macrophages, B cells or T cells) that regulate a wide range of immune system functions. The functions of different ILs vary from regulating inflammatory and immune responses, functioning as autocrine factor and regulating and/or inhibiting other ILs. IL-12 is secreted by macrophages and human B-lymphoblastoid cells in response to antigenic stimulation. It is responsible for the differentiation of naive CD4+ T cells into type 1 helper T cells that produce interferon-γ (IFN-γ). It also activates production of tumor necrosis factor α (TNFα) from T and natural killer (NK) cells, and it inhibits IL-4 mediated suppression of IFN-γ. IL-12 also has antiangiogenic activity, since the production of IFN-γ increases the production of inducible protein-10 (IP-10).