Publications (21) View all
-
Article: Prevention of diabetes in NOD mice by administration of dendritic cells deficient in nuclear transcription factor-kappaB activity.
[show abstract] [hide abstract]
ABSTRACT: Abnormalities of dendritic cells (DCs) have been identified in type 1 diabetic patients and in nonobese diabetic (NOD) mice that are associated with augmented nuclear transcription factor (NF)-kappaB activity. An imbalance that favors development of the immunogenic DCs may predispose to the disease, and restoration of the balance by administration of DCs deficient in NF-kappaB activity may prevent diabetes. DCs propagated from NOD mouse bone marrow and treated with NF-kappaB-specific oligodeoxyribonucleotide (ODN) in vitro (NF-kappaB ODN DC) were assessed for efficacy in prevention of diabetes development in vivo. Gel shift assay with DC nuclear extracts confirmed specific inhibition of NF-kappaB DNA binding by NF-kappaB ODN. The costimulatory molecule expression, interleukin (IL)-12 production, and immunostimulatory capacity in presenting allo- and islet-associated antigens by NF-kappaB ODN DC were significantly suppressed. NF-kappaB ODN renders DCs resistant to lipopolysaccharide stimulation. Administration of 2 x 10(6) NF-kappaB ODN DCs into NOD mice aged 6-7 weeks effectively prevented the onset of diabetes. T-cells from pancreatic lymph nodes of NF-kappaB ODN DC-treated animals exhibited hyporesponsiveness to islet antigens with low production of interferon-gamma and IL-2. These findings provide novel insights into the mechanisms of autoimmune diabetes and may lead to development of novel preventive strategies.Diabetes 09/2003; 52(8):1976-85. · 8.29 Impact Factor -
Article: Use of recombinase activation gene-2 deficient mice to ascertain the role of cellular and humoral immune responses in the development of chronic rejection.
[show abstract] [hide abstract]
ABSTRACT: Given its multifactorial etiology, the relative contribution of anti-donor cellular and humoral immune responses in the pathogenesis of chronic rejection is as yet ambiguous. We hypothesized that alloreactive T and B cells play a seminal role in the development of this lesion. To address this hypothesis, RAG-2(-/-) mice were used as donors and recipients in a well-established murine model of aortic transplantation. Grafts were transplanted across the following groups: Group I: C3H --> C3H; Group II: Wild-type [WT] 129Sv (H-2(b)) --> C3H (H-2(k)); Group III: C3H --> WT 129Sv; Group IV: 129SvEv RAG-2(-/-) --> C3H; and Group V: C3H --> 129SvEv RAG-2(-/-). Grafts were harvested at d40 to 146 post-transplantation for morphologic and immunohistochemical analyses and semi-quantitative RT-PCR was employed to evaluate the intragraft mRNA expression of various immune mediators. Mixed lymphocyte reaction and complement-mediated alloantibody cytotoxicity assays were performed to determine anti-donor proliferative and humoral responses, respectively. Unlike that across the syngeneic combination (Group I), marked intimal thickening with corresponding luminal narrowing was observed in the majority of the aortic allografts (Groups II-IV). On the contrary, the morphology of C3H aortic allografts harvested from the majority of the RAG-2(-/-) was remarkably preserved. Correspondingly, anti-donor proliferative and humoral immune responses were undetectable in C3H --> RAG-2(-/-) recipients as was the intragraft mRNA expression of the Th(1) and the Th(2)-type cytokines. Taken together, these data suggest that in this murine model of aortic allotransplantation, donor-specific cellular and humoral responses play a dominant role in the initiation and perpetuation of chronic rejection.The Journal of Heart and Lung Transplantation 07/2002; 21(7):738-50. · 4.33 Impact Factor -
Article: Flt3-L augments the engraftment of donor-derived bone marrow cells when combined with sublethal irradiation and costimulatory (CD28/B7 and CD40/CD40L) blockade.
[show abstract] [hide abstract]
ABSTRACT: T-cell costimulatory blockade as a constituent for recipient conditioning prior to bone marrow transplantation has led to the development of less toxic protocols for the establishment of donor cell chimerism. We therefore hypothesized that the addition of the hematopoietic growth factor, Flt3-ligand (Flt3-L), to the perioperative inhibition of the CD28/B7 and CD40/CD40 ligand costimulatory pathways would enhance the engraftment of allogeneic bone marrow. Recipient BALB/c ByJ (H-2(d), Mls(c), Vbeta6+/Vbeta8+ TCR) received a single sublethal dose of total body irradiation (300 rad) 6 h prior to transplantation IV with unfractionated donor CBA/J (H-2(k), Mls(d), Vbeta6-/Vbeta8+ TCR) bone marrow cells. CTLA4-Ig and/or MRI were administered at 500 microg IP on days 0, 2, 4, and 6 posttransplantation. Flt3-L was administered at 10 microg IP on days 0-6. Donor cell chimerism was determined on days 30-90 by flow cytometric analysis. Donor-specific tolerance was assessed by skin grafting. In vitro TCR cross-linking assays and flow cytometry were utilized to explore the deletion of donor-reactive T cells. Recipients receiving CTLA4-Ig and MRI engrafted allogeneic bone marrow cells in the peripheral blood (3/6; 50%) with chimerism being detected at 2-31%. Addition of Flt3-L to this preconditioning regimen enhanced the incidence of engraftment of donor bone marrow cells (10/13; 3-70%). Long-term survival of donor but not third-party-specific skin grafts demonstrated that donor-specific tolerance had been achieved in the chimeric recipients. Deletion of the donor-reactive T cells within the chimeric recipients was also observed. The addition of hematopoietic growth factors and cytokines to the nonmyeloablative regimen of sublethal irradiation and T-cell costimulatory blockade provides a novel strategy for the establishment of donor cell chimerism and for the induction of stable and robust donor-specific tolerance. The deletion of donor-reactive T cells using this protocol suggests the reliability and feasibility of this protocol for clinical transplantation.Cell Transplantation 02/2002; 11(2):147-59. · 5.13 Impact Factor -
Article: Enhanced allograft survival via simultaneous blockade of transferrin receptor and interleukin-2 receptor.
[show abstract] [hide abstract]
ABSTRACT: Transferrin receptor (TfR) expression follows the induction of interleukin 2 receptor (IL-2R) expression in a sequence that is necessary to initiate cell proliferation in quiescent T lymphocytes. Therefore, we tested the hypothesis that simultaneous blockade of TfR and IL-2R would be more effective in prolonging allograft survival and suppressing T-cell responses to alloantigen than single receptor blockade by modifying T-cell effectors to alloantigen. Neonatal C57BL/6 hearts were transplanted to CBA/J recipients in a heterotopic, nonvascularized cardiac allograft model. Anti-TfR and/or anti-IL-2R or isotype-matched control monoclonal antibodies (mAbs) were administered at 100 microg intravenously on days 0 and 1 of transplantation. Anti-TfR mAb (25.7+/-0.9 days) significantly (P<0.01) prolonged cardiac allograft survival compared with anti-IL-2R mAb (12.5+/-0.9 days) or the isotype control (15.7+/-1.2 days, P<0.01, Wilcoxon rank-sum). Anti-TfR plus anti-IL-2R mAbs significantly (P<0.01) prolonged cardiac allograft survival to 50.7+/-2.0 days compared with the isotype control or either agent alone. These agents in combination down-regulated the intragraft T helper (Th)-1 cytokines, IL-2, interferon-gamma, and IL-15, while up-regulating the Th2 cytokine, IL-4, and completely abrogating the antigen-presenting cell IL-12p40 mRNA expression. Anti-TfR and anti-IL-2R mAbs are potent immunosuppressants. Combined blockade of TfR and IL-2R at the time of antigen presentation seems to be the most effective by shifting the intragraft Th cytokine paradigm.Transplantation 11/1999; 68(9):1369-76. · 4.00 Impact Factor -
Article: T-Cell Alterations in Cardiac Allograft Recipients After B7 (Cd80 and Cd86) Blockade1
[show abstract] [hide abstract]
ABSTRACT: Background. T-cell activation requires engagement of the T cell receptor with the antigen-MHC and simultaneous ligation of the coreceptor CD28. CD28 binds both the CD80 (B7-1) and CD86 (B7-2) ligands on antigen-presenting cells. The functional role of these costimulatory pathways in transplantation is not completely understood. We tested the hypothesis that in vivo blockade of the CD28 pathway via the anti-CD80 and anti-CD86 monoclonal antibodies (mAbs) would prolong allograft survival. Methods. Neonatal C57BL/6J (H22) hearts were transplanted to CBA/J(H2k) recipients in a heterotopic nonvascularized model, with anti-CD80 and/or anti-CD86 mAbs being administered intravenously at the time of allografting (day 0) and on the following day (day 1). Results. Anti-CD80 mAb (29.8±1.5 days) and anti-CD86 mAb (30.8±0.5 days) alone significantly prolonged allograft survival compared with the isotype control (10.7±0.4 days, P<0.01, Wilcoxon rank sum). The concurrent (days 0 and 1) and sequential administration of anti-CD86 mAb on days 0 and 1 plus anti-CD80 mAb on days 2 and 3 prolonged allograft survival to >80 days. Simultaneous administration of anti-CD80 and anti-CD86 mAbs significantly suppressed donor-specific cytotoxic T lymphocyte responses to alloantigen. Anti-CD86 mAb suppressed intragraft interleukin (IL)-4, IL-10, IL-12 p40, and IL-15 mRNA expression. Conclusions. Anti-CD80 and/or anti-CD86 mAbs are potent immunosuppressants in prolonging allograft survival. Combined blockade of the B7 (CD80 and CD86) ligands seems to be the most effective in prolonging allograft survival and suppressing donor-specific allogeneic cytotoxic T lymphocyte responses. In vivo blockade of CD86, in comparison to CD80, had the greatest immunosuppressive effect on day 7 intragraft cytokines, suggesting its role on early allogeneic immune responses.Transplantation 07/1998; 66(1):14-20. · 4.00 Impact Factor
