Antigen Loading (e.g., Glutamic Acid Decarboxylase 65) of Tolerogenic DCs (tolDCs) Reduces Their Capacity to Prevent Diabetes in the Non-Obese Diabetes (NOD)-Severe Combined Immunodeficiency Model of Adoptive Cotransfer of Diabetes As Well As in NOD Mice.

David P Funda,Jaroslav Goliáš,Lenka Palová-Jelínková,Hana Kozáková,Radek Špíšek,Tomáš Hudcovic

doi:10.3389/fimmu.2018.00290

Abstract

Tolerogenic DCs (tolDCs) are being researched as a promising intervention strategy also in autoimmune diseases including type 1 diabetes (T1D). T1D is a T-cell-mediated, organ-specific disease with several well-defined and rather specific autoantigens, i.e., proinsulin, insulin, glutamic acid decarboxylase 65 (GAD65), that have been used in animal as well as human intervention trials in attempts to achieve a more efficient, specific immunotherapy. In this study, we have tested tolerogenic DCs for their effectiveness to prevent adoptive transfer of diabetes by diabetogenic splenocytes into non-obese diabetes (NOD)-severe combined immunodeficiency (NOD-SCID) recipients. While i.p. application of tolDCs prepared from bone marrow of prediabetic NOD mice by vitamin D2 and dexamethasone significantly reduced diabetes transfer into the NOD-SCID females, this effect was completely abolished when tolDCs were loaded with the mouse recombinant GAD65, but also with a control protein—ovalbumin (OVA). The effect was not dependent on the presence of serum in the tolDC culture. Similar results were observed in NOD mice. Removal of possible bystander antigen-presenting cells within the diabetogenic splenocytes by negative magnetic sorting of T cells did not alter this surprising effect. Tolerogenic DCs loaded with an immunodominant mouse GAD65 peptide also displayed diminished diabetes-preventive effect. Tolerogenic DCs were characterized by surface maturation markers (CD40, CD80, CD86, MHC II) and the lipopolysaccharide stability test. Data from alloreactive T cell proliferation and cytokine induction assays (IFN-γ) did not reveal the differences observed in the diabetes incidence. Migration of tolDCs, tolDCs-GAD65 and tolDCs-OVA to spleen, mesenteric- and pancreatic lymph nodes displayed similar, mucosal pattern with highest accumulation in pancreatic lymph nodes present up to 9 days after the i.p. application. These data document that mechanisms by which tolDCs operate in vivo require much better understanding for improving efficacy of this promising cell therapy, especially in the presence of an antigen, e.g., GAD65.

Highlights

Type 1 diabetes (T1D) is a T cell-mediated disease, in which both CD4 and CD8 T cells are necessary and sufficient in precipitating the disease by targeting very relatively small volume of highly specialized beta-cells within Islets of Langerhans [1, 2]
We found out that tolerogenic dendritic cell (tolDC) that were cultured from day 7 with mouse glutamic acid decarboxylase 65 (GAD65) (2 μg/mL) completely lost their diabetes-preventive properties when cotransferred with diabetogenic splenocytes from 13-week-old prediabetic Non-obese diabetes (NOD) females to NOD-SCID recipients (n = 12)
We have shown that antigen-unloaded tolDCs consistently decreased diabetes transfer in the NOD-SCID model of adoptive cotransfer of diabetes (Figures 1–3)

Summary

Introduction

Type 1 diabetes (T1D) is a T cell-mediated disease, in which both CD4 and CD8 T cells are necessary and sufficient in precipitating the disease by targeting very relatively small volume of highly specialized beta-cells within Islets of Langerhans [1, 2]. While the NOD spontaneous mouse model allows to study the natural course of the disease in its complexity, NOD-SCID mice with adoptively cotransferred diabetogenic NOD splenocytes are often used for testing regulatory/protective capacity of various cell subsets in a shorter timeframe [3]. It has been shown that bone marrow-derived tolerogenic DCs (tolDCs) generated in the presence of GM-CSF and IL-4 in an antigen-nonspecific manner displayed diabetespreventive properties [8, 9]. TolDCs pulsed with apoptotic bodies containing beta-cell antigens decreased diabetes and insulitis in a transgenic NOD model of accelerated diabetes [13]. While data from Pujol-Autonell et al documented that reverting diabetes in already diabetic animals might be difficult [14], genetically engineered bone marrow-derived DCs transduced with IL-4 were able to prevent diabetes in 12-week-old prediabetic NOD mice with advanced insulitis [15]

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Conclusion