Autoantigen-specific protection of non-obese diabetic mice from cyclophosphamide-accelerated diabetes by vaccination with dendritic cells

Abstract

Dendritic cells (DCs) are professional antigen presenting cells involved in the initiation of primary immune responses and the preservation of peripheral tolerance. The aim of this study was to develop a DC vaccine for autoantigen-specific prevention of autoimmune diabetes. Splenocytes from diabetes-prone NOD mice were cultured in conditioned media to obtain a homogeneous DC sub-population for vaccination experiments. These cells were used to modulate autoimmune responses in NOD mice after synchronization of diabetes with cyclophosphamide. After immunisation with insulin-pulsed DCs the incidence of diabetes, the insulitis grade and the cytokine production was examined. The long-term culture of splenocytes resulted in the generation of a cell line, termed NOD-DC1, which have a phenotype of myeloid DCs (CD11c, CD11b, DEC-205), express MHC class II and co-stimulatory molecules (CD40, CD80, CD86). The NOD-DC1 cells have preserved functional activity shown by the detection of a high antigen uptake capacity, the induction of a mixed lymphocyte reaction and stimuli-dependent IL-6 and TNF-alpha secretion. Vaccination with insulin-pulsed NOD-DC1 cells results in an antigen-specific prevention of diabetes. This was mediated by a reduction of the severity of insulitis and a decrease of T helper 1 effector cells. We describe the generation of a DC line which confers protection from diabetes in an antigen-specific way. Our data shows that autoantigen-loaded DCs can induce strong immunoregulatory effects supporting the hypothesis that DCs are promising candidates to develop novel vaccines for the prevention of autoimmune diabetes.