Downregulation of IL-17 and IFN-γ in the optic nerve by β-elemene in experimental autoimmune encephalomyelitis

Backgroundβ-elemene is a natural antitumor plant drug. Beneficial effects of β-elemene therapy have been demonstrated in some kinds of tumor clinically. Especially, it has been found to pass through the blood brain barrier easily. Other reports have indicated that immune disorder that appeared in some tumors usually can be seen in demyelinating diseases including multiple sclerosis and experimental autoimmune encephalomyelitis. However, no information regarding the effects of β-elemene therapy on the T helper cell subsets, Th1 or Th17 cells in experimental autoimmune encephalomyelitis has been found.Methods and findingsWe first determined morphologically that β-elemene therapy markedly suppressed the inflammation in experimental autoimmune encephalomyelitis optic nerve. We then determined the effect in vivo of β-elemene on Treg cells and Th17 and Th1 cells. We found that β-elemene treatment modulated immune balance in both the periphery and the inflamed optic nerve by promoting less downregulation in Treg cells, inhibiting Th17 and Th1 polarization.ConclusionsTaken together, our finding reveals an important new locus where β-elemene induces substantial protection in experimental autoimmune encephalomyelitis optic nerve through signaling to several critical subsets of immune cells that reside in the peripheral and central nervous system.