Donor CD8+ T cells facilitate induction of chimerism and tolerance without GVHD in autoimmune NOD mice conditioned with anti-CD3 mAb

Abstract

IntroductionType 1 diabetes is an autoimmune disease characterized by destruction of insulin-secreting pancreatic islet ␤ cells by pathogenic autoreactive T cells. 1,2 By most accounts, the nonobese diabetic (NOD) mouse represents an ideal animal model for human type 1 diabetes. 3 Female NOD mice develop insulitis at about 4 weeks of age and begin to show diabetes from about 15 weeks of age. 3 Induction of mixed chimerism via transplantation of bone marrow (BM) cells from nonautoimmune donors into autoimmune NOD mice has been shown to reverse insulitis and prevent the development of diabetes and induce tolerance to donor islet cells. [4][5][6][7][8] However, the bone marrow transplantation (BMT) procedures require nonmyeloablative total body irradiation (TBI) conditioning of the recipients. [4][5][6][7][8] The toxicity of TBI conditioning and potential for graft-versus-host disease (GVHD) prevents the application of BMT to treating type 1 diabetes and the induction of immune tolerance for islet cell transplantation. 9 This underlies the need for a radiation-free regimen. However, a radiation-free regimen that induces mixed chimerism in autoimmune mice has not been described, although administration of costimulatory blockade (anti-CD40L) has been reported to induce mixed chimerism in nonautoimmune mice. 10,11 GVHD in TBI-conditioned recipients is caused by both TBIconditioning procedures and donor T-cell attack of host epithelial tissues such as gut, skin, and liver. 12 TBI conditioning plays a critical role in initiating the tissue damage and inflammatory cascade. [13][14][15] The TBI-damaged host tissues release inflammatory cytokines (ie, tumor necrosis factor ␣ [TNF-␣], interleukin 6 [IL-6], and IL-1) and chemokines. Additionally, the gut tissue damage caused by TBI allows the release of lipopolysaccharide (LPS) from intestinal flora, which induces a wide range of secondary inflammatory actions. The inflammatory cytokines and chemokines induce the maturation and activation of host antigenpresenting cells (APCs), and the activated host APCs activate donor T cells. 16 The activated donor T cells up-regulate chemokine receptors in response to inflammatory chemokines and cytokines and migrate to inflammatory epithelial tissues and differentiate into Type-1 T helper (Th 1 ) and Type-2 cytotoxic T (Tc 1 ) cells. The Th 1 cells release inflammatory cytokines (such as interferon ␥ [IFN-␥] and TNF-␣) that further enhance local inflammation, and the Tc 1 cells attack the host tissues so that GVHD occurs. 14 GVHD in TBI-conditioned recipients can be prevented by depletion of donor T cells, but depletion of donor T cells results in a marked increase in engraftment failure. 17 Donor CD8 ϩ T cells play a critical role in facilitating donor stem cell engraftment in both murine and human BM transplant recipients, although they contribute to GVHD induction in TBI-conditioned recipients. [18][19][20] It was previously reported that donor T-cell infusion after the waning of inflammatory responses induced by TBI conditioning con...

Elimination of insulitis and augmentation of islet β cell regeneration via induction of chimerism in overtly diabetic NOD mice

“…In addition, the HCT procedures used in those reports require total body irradiation conditioning of the recipients, and the toxicity of radiation and potential for graft-versushost disease (GVHD) limits its application in treating type 1 diabetic patients. We recently reported that transplantation of allogeneic donor BM and CD8 ϩ T cells into prediabetic NOD mice conditioned with anti-CD3 mAb induced chimerism without causing GVHD (27). In the current study, we showed that injection of donor BM and CD4 ϩ T cell-depleted spleen (SPL) cells induced chimerism in diabetic NOD mice conditioned with anti-CD3 and anti-CD8 mAb (anti-CD3/CD8).…”

“…This radiation-free regimen provides for induction of chimerism without GVHD in overtly diabetic NOD mice, and we demonstrate that this chimerism augments the regeneration of host islet ␤ cells. two injections of 20 ϫ 10 6 donor CD8 ϩ T cells (27). However, we also observed that the same dose of donor BM and CD8 ϩ T cells did not induce chimerism in diabetic NOD mice, whose blood glucose had been controlled with implantation of insulin pellets (data not shown).…”

“…The donor CD4 ϩ T cell-depleted SPL cells were injected again 5 days after injection. Thereafter, the recipients were monitored for clinical signs of GVHD and blood glucose levels as described previously (27).…”

“…Anti-CD3 (145-2C11) and anti-CD8 (116-13.1) antibodies were produced as described previously (27). Diabetic NOD/LtJ mice were implanted with insulin pellets following the vendor's instruction (Linshin, Toronto, ON, Canada), then injected i.v.…”

“…The following antimouse mAbs were purchased from BD Biosciences PharMingen (San Diego, CA) and eBioscience (San Diego, CA): CD3 (145-2C11), TCR␤ (H57-597), CD4 (RM4-5), CD8␣ (53-6.7), B220 (RA3-6B2), CD11b/Mac-1 (M1/70), and Gr-1(RB6-8C5). FACS was performed with a four-laser MOFLO immunocytometry system (Dako Cytomation, Fort Collins, CO), and data were analyzed with FLOWJO software (Tree Star, San Carlos, CA) as described previously (27).…”