Flt3L-Derived Antigen-Presenting Cell Transfer in Neonatal NOD Mice Reduces the Incidence of Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune disease characterized by progressive stages culminating in T-cell-mediated destruction of the β-cells at the islets of Langerhans. The immune mechanisms that initiate T1D are not fully resolved but likely involve an interaction between proinflammatory antigen-presenting cells (APCs) and autoreactive T cells that initiate immune infiltration and activation. Previous studies have tested the use of tolerogenic APCs in adult female NOD mice to delay or prevent T1D with only slight to intermediate success. Moreover, immune infiltration begins as early as age 4 weeks; therefore, targeting autoreactive T cells with tolerogenic APCs in adult mice may not impact later stages of diabetes. Thus, we hypothesize that the transfer of tolerogenic APCs at the neonatal stage prior to priming and immune infiltration will result in effective protection from autoimmunity. Our studies demonstrate that immature APCs travel to the pancreatic draining lymph nodes, alter the cytokine milieu in young mice, divert autoreactive CD4+ T cells to anergy, and drastically decrease proliferation and function of cytotoxic lymphocytes in adult prediabetic mice, leading to a significant reduction in the incidence of T1D.

Neonatal transfer of immature dendritic cell-enriched Flt3L splenocytes significantly reduces the incidence of type 1 diabetes in female NOD mice. Early time points are associated with accumulation of anergic T cells. In adult mice, there is a reduction in CD4 T helper 1 cells and reduced proliferation and perforin of CD8 T cells. Our work demonstrates how targeting the neonatal window of tolerance alters autoimmunity outcome.