The pro- and anti-inflammatory properties of the cytokine interleukin-6

► The cytokine interleukin-6 (IL-6) has pro- and anti-inflammatory properties. ► Whereas only few cells express the IL-6 receptor and respond to IL-6 (classic signaling), all cells can be stimulated via a soluble IL-6 receptor (trans-signaling) since gp130 is ubiquitously expressed. ► Classic- and trans-signaling can be differentially inhibited. ► Apparently, IL-6 via classic signaling has regenerative and anti-inflammatory functions whereas trans-signaling is pro-inflammatory.