Transplantation of Bone Marrow Transduced to Express Self-Antigen Establishes Deletional Tolerance and Permanently Remits Autoimmune Disease

Abstract

Autoimmune diseases are incurable. We have hypothesized that these diseases can be cured by the transplantation of bone marrow (BM) stem cells that have been genetically engineered to express self-Ag. Here we have tested this hypothesis in experimental autoimmune encephalomyelitis (EAE) induced by the self-Ag myelin oligodendrocyte glycoprotein (MOG). We show that, in mice, transplantation of BM genetically modified to express MOG prevented the induction and progression of EAE, and combined with antecedent corticosteroid treatment, induced long-term remission of established disease. Mice remained resistant to EAE development upon subsequent rechallenge with MOG. Transfer of BM from these mice rendered recipients resistant to EAE. Splenocytes from these mice failed to proliferate or produce IL-17, IFN-γ, and GM-CSF in response to MOG35–55 peptide stimulation and they failed to produce MOG autoantibody. Mechanistically, we demonstrated in vivo reduction in development of CD4+ MOG35–55-specific thymocytes, indicative of clonal deletion with no evidence for selection of Ag-specific regulatory T cells. These findings validate our hypothesis that transplantation of genetically modified BM expressing disease-causative self-Ag provides a curative approach by clonal deletion of disease-causative self-reactive T cells.

Non-myeloablative transplantation of bone marrow expressing self-antigen establishes peripheral tolerance and completely prevents autoimmunity in mice

“…In contrast to 1100 cGy disease-resistant and naive mice where their splenocytes failed to proliferate in response to MOG peptide even at 100 mg ml À1 , 6 splenocytes from 275 cGy mice proliferated to MOG peptide at 100 mg ml À1 . These results indicate the presence of peripheral MOG-reactive T cells in disease-resistant mice ( Figure 4a).…”

“…6 Here we investigated whether transplantation of pMOG-BM with lower doses of irradiation would provide a similar preventive effect. We used stepwise reduction of irradiation doses of 770, 550, 412, 275, 100, 50, 20 or 5 cGy.…”

“…The 275 cGy group showed no cellular infiltration and demyelination (Table 1). Dose-dependent molecular chimerism levels in relation to irradiation dose Because all experiments carried out in this study use sorted green fluorescent protein (GFP) þ pMOG-BM cells and GFP expression can be used as a marker for molecular chimerism of MOG protein expression, 6 chimerism can be assessed based on GFP expression. Indeed, BMcells transduced with pMOG were shown to co-express GFP and MOG protein (Figure 3a).…”

“…1 --5 Using myelin oligodendrocyte glycoprotein peptide 33 --55 (MOG 35À55 ) induced experimental autoimmune encephalomyelitis (EAE) as a model of multiple sclerosis, we have shown that transplantation of syngeneic bone marrow (BM) can be associated with disease remission but recipient mice retained susceptibility to EAE upon MOG 35À55 re-immunization. 6 Thus, data from human clinical trials and animal studies indicate that autologous/syngeneic BMT alone is insufficient to provide a cure. Transplantation of genetically modified hematopoietic stem cells using retroviral vectors has been used to treat human immunodeficiency disorders.…”

“…Transplantation of genetically modified hematopoietic stem cells using retroviral vectors has been used to treat human immunodeficiency disorders. 7 --9 In autoimmunity, using lethal-myeloablative pre-conditioning, we have demonstrated that transplantation of BM genetically engineered to express MOG provided EAE resistance in recipient mice, even after multiple immunization challenges 6 and showed central deletional tolerance as a mechanism of resistance.…”