462 Protective potential of murine tolerogenic dendritic cells in rat-to-mouse islets xenotransplantation model
Tuesday November 17, 2015 from 11:00 to 12:30
Room 110

Natacha Madelon, Switzerland

PhD student

Division of Immunology and Allergology

Geneva University Hospitals


Protective potential of murine IL-10-induced tolerogenic dendritic cells in rat-to-mouse islets xenotransplantation model

Natacha Madelon1, Elisa Montanari2, Yannick D Muller1, Lyssia Gruaz1, Joel Pimenta2, Leo H Buhler2, Gisella Puga Yung1, Jörg D Seebach1.

1Laboratory of Transplantation and Immunology, Department of Medical Specialties, Geneva University Hospitals, Medical Faculty, Geneva, Switzerland; 2Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals, Medical Faculty, Geneva, Switzerland

Laboratory of Transplantation and Immunology. Cell Isolation and Transplantation Center.

Introduction: Dendritic cells (DC) are professional antigen presenting cells playing a crucial role in xenogeneic immune responses. DC maturation can be influenced by different environmental stimuli, triggering either strong immune responses or inducing immune tolerance. This DC plasticity has been used to generate tolerogenic DC in vitro from different progenitor cells by treatment with anti-inflammatory cytokines, in particular interleukin 10 (IL-10). Adoptive transfer of in vitro differentiated tolerogenic DC has been shown to prolong allograft survival in several murine models of skin, heart and islets allotransplantation; however the potential of tolerogenic DC to protect xenografts remains unexplored. In this study, we investigated the potential of in vitro differentiated murine tolerogenic DC obtained by culture in IL-10 (IL-10-DC) to protect xenografts in a rat-to-mouse islets transplantation model.
Methods: Bone marrow cells were removed from femurs and tibias of C57BL/6 mice and cultured for 7 days in the presence of GM-CSF alone to differentiate into DC, or in combination with IL-10 to obtain IL-10-DC. DC maturation induced by LPS was evaluated by measuring the expression of co-stimulatory molecules, MHC class I and II by flow cytometry; and cytokine production by ELISA. The potential of IL-10-DC to inhibit polyclonal CD4+ and CD8+ T responses induced by anti-mouse CD3 antibodies was investigated in vitro by thymidine proliferation assays. Streptozotocin-induced diabetic C57BL/6 mice were transplanted under the kidney capsule with 500 IEQ rat islets, mixed or not with 2x106 murine DC or IL-10-DC. Xenograft survival was monitoring by measuring glycemia.
Results: Compared to untreated DC, IL-10-DC expressed similar levels of MHC class I but lower levels of the co-stimulatory molecules CD80, CD86 and of MHC class II following LPS stimulation. IL-10-DC produced similar levels of IL12p70 and TNFα as untreated DC, but secreted higher levels of IL-10 in response to LPS stimulation. In vitro, IL-10-DC significantly inhibited polyclonal CD4+ and CD8+ T cell proliferation, with an inhibition of T cell proliferation of 57% and 67%, respectively. Preliminary results showed that mice transplanted with rat islets and untreated murine DC had a median xenograft survival of 12 days. By contrast, mice co-transplanted with murine IL-10-DC presented a median xenograft survival of 35 days.
Conclusion: Taken together, murine IL-10-DC presented defective LPS maturation as shown by decreased expression of MHC class II and co-stimulatory molecules and inhibited polyclonal CD4+ and CD8+ T cell proliferation in vitro. Moreover, our preliminary results indicate that in vitro differentiated tolerogenic IL-10-DC could be used as cell-based therapy to protect islet xenografts and improve xenograft tolerance.

SNF grants # 320030_138376 and 310030_159594.

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