Anti-IL-6R prevents experimental type 1 diabetes

Abstract Type 1 diabetes (T1D) is an autoimmune disease, where the insulin producing β cells are damaged by immune attacks leading to a failure of blood glucose control. The anti-inflammatory cytokine IL-35 has been shown to prevent and reverse T1D in mouse models. IL-6 signals through a homodimer of gp130 which is one of the receptors of IL-35. We thus hypothesized that blocking IL-6 signaling would facilitate IL-35 signaling and prevent T1D. We used multiple low dose streptozotocin (MLDSTZ) to induce T1D in male CD-1 mice and treated them with anti-IL-6R to study the immune response. We found that anti-IL-6R treatment prevented MLDSTZ mice from developing hyperglycemia, and preserved the ability of β cells to produce insulin. We then used flow cytometry to investigate the T cell and B cell response on day 13 after the first injection of MLDSTZ. The proportions of Treg cells were not altered by anti-IL-6R treatment in MLDSTZ treated mice, but the treatment elevated the proportions of IL-35 producing Treg cells in the spleen and thymus. It also decreased IFN-γ production in CD4, CD8, Treg and B cells in the spleen. Furthermore, anti-IL-6R treatment only tended to increase IL-17 production in CD4, CD8 and Treg cells. Altogether, our data demonstrate that anti-IL-6R treatment prevents T1D in MLDSTZ mice by maintaining the Treg cell phenotype and by reducing IFN-γ production by T and B cells.