Gene Transfer of Ig-Fusion Proteins Into B Cells Prevents and Treats Autoimmune Diseases

Abstract

Based on the tolerogenic properties of IgG carriers and B cell Ag presentation, we developed a retrovirally mediated gene expression approach for treatment of autoimmune conditions. In this study, we show that the IgG-Ag retroviral constructs, expressing myelin basic protein (MBP) or glutamic acid decarboxylase in B cells, can be used for the treatment of murine models for multiple sclerosis and diabetes. Transduction of syngeneic B cells with MBP-IgG leads to the amelioration of ongoing experimental allergic encephalomyelitis induced by the transfer of primed cells from PL×SJL F1 mice with ongoing disease and could be effective even after symptoms appeared. This effect is specific and does not involve bystander suppression because treatment with MBP-IgG does not affect disease induced after immunization with proteolipid protein immunodominant peptide plus MBP. Interestingly, if donor B cells are derived from gld mice (Fas ligand-negative), then tolerance is not induced with a model Ag although there was no evidence for Fas ligand-mediated deletion of target T cells. In spontaneous diabetes in nonobese diabetic mice, we were able to stop the ongoing autoimmune process by treatment at 7–10 wk with glutamic acid decarboxylase-IgG retrovirally transduced B cells, or attenuate it with B cells transduced with an insulin B chain (B9–23) epitope IgG fusion protein. Furthermore, IgG fusion protein gene therapy can also protect primed recipients from Ag-induced anaphylactic shock, and thus does not cause immune deviation. These results demonstrate proof of principle for future efforts to develop this approach in a clinical setting.

Retroviral delivery of GAD-IgG fusion construct induces tolerance and modulates diabetes: a role for CD4+ regulatory T cells and TGF-β?

“…When this Ig-fusion protein was delivered into bone marrow (BM)-derived cells or lipopolysaccharide (LPS)-stimulated B cells via retroviral infection, and then these cells were injected into syngeneic recipients, the recipients were rendered significantly hyporesponsiveness to specific epitopes of the antigen. [3][4][5][6][7][8][9][10] Results with this gene therapy protocol demonstrated that it was simple and effective, even in primed recipients and autoimmune animals, including preliminary studies with spontaneous diabetes in nonobese diabetic (NOD) mice. 6,10 However, the precise mechanism of tolerance induction in this system is not well understood.…”

“…[3][4][5][6][7][8][9][10] Results with this gene therapy protocol demonstrated that it was simple and effective, even in primed recipients and autoimmune animals, including preliminary studies with spontaneous diabetes in nonobese diabetic (NOD) mice. 6,10 However, the precise mechanism of tolerance induction in this system is not well understood. We know that tolerance does not involve a Th1/Th2 shift, 4,10 that major histocompatibility complex (MHC) class II expression on the presenting B cells is important and B cells are critical antigen-presenting cells (APCs), 7 but that Fc receptors are not required.…”

“…6,10 However, the precise mechanism of tolerance induction in this system is not well understood. We know that tolerance does not involve a Th1/Th2 shift, 4,10 that major histocompatibility complex (MHC) class II expression on the presenting B cells is important and B cells are critical antigen-presenting cells (APCs), 7 but that Fc receptors are not required. 8 To further examine the mechanism of tolerance induction by retroviral delivery of Ig tolerogens in B cells, we utilized this gene transfer approach in the treatment of spontaneous diabetes in NOD mice, an animal model for human insulin-dependent diabetes mellitus (IDDM).…”

“…11 The 65 kDa form of glutamic acid decarboxylase (GAD65) has been shown to be a key islet cell autoantigen in the induction of diabetes in NOD mice. 10 The initial autoimmunity to GAD65 triggers a spreading T-cell response to other pancreatic b-cell antigens; importantly, tolerance induction to GAD65 can block the spreading to other b-cell antigens, thus preventing diabetes. 12,13 In this study, a retroviral construct encoding full-length pathogenic murine GAD65 at the N-terminus of murine IgG scaffold was used to treat NOD mice by delivering retrovirally genetransfected LPS-stimulated splenocytes.…”

Cell-based gene therapy experiments in murine experimental autoimmune encephalomyelitis

“…B cells transduced with a vector encoding PLP (100-154) as well as B cells expressing a MBP-Ig fusion protein were shown to ameliorate ongoing disease. 51,52 We have used a diploid, untransformed, transduced fibroblast line secreting PLP (101-157) to successfully treat EAE mice. 30 In addition, our protocol was designed to deliver a low-level, constant exposure to antigen, and this may be the reason we have never observed the anaphylactic response seen in some cases upon repeated injection of antigen.…”