Ingested (oral) SIRS peptide 1–21 inhibits acute EAE by inducing Th2-like cytokines

ObjectiveIngested type I IFN inhibits clinical attacks, relapses and inflammation in murine chronic relapsing EAE by inhibiting Th1-like cytokines. Type I IFN activates human suppressor T cells that produce SIRS.MethodsWe examined whether oral (ingested) SIRS peptide inhibits EAE by decreasing Th1-like cytokines.ResultsParenteral SIRS peptide 1–21 showed a significant inhibition of disease severity in murine EAE. Ingested SIRS peptide at 10 and 100 μg SIRS peptide showed a significant inhibition of disease severity but also a prolonged delay in the onset of disease compared to placebo. There were significantly less inflammatory foci in the SIRS peptide fed group compared to the control mock fed group. Splenocytes from SIRS peptide 1–21 fed mice showed increased production of Th2-like CD30L, IL-13, TCA-3 cytokines/chemokines and decreased production of Th1-like cytokine lymphotactin.InterpretationIngested (oral) SIRS peptide significantly inhibits both clinical EAE and inflammation predominately via counter-regulatory type 2-like cytokines/chemokines IL-13, CD30L and TCA-3.