IL-12 family members in experimental colitis.

Interleukin (IL)-12 p35/p40 is a heterodimeric cytokine that plays an important role in T helper (Th) cell polarization and Th1 T-cell differentiation. Recent findings have shown that both p35 and p40 can form other cytokines with different proteins (IL-23: p19/p40; IL-35: p35/EBI3). Furthermore, the cytokine IL-27 (EBI3/p28) has been identified as a member of the IL-12 family. Here, we discuss the recent findings on the role of IL-12 family members in experimental colitis. In particular, the role of IL-23 as a master regulator of effector T-cell activation is highlighted. These findings have important implications for the design of new therapeutic approaches in chronic intestinal inflammation in humans.