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Li XC, Li Y, Dodge I, Wells AD, Zheng XX, Turka LA, Strom TB. Induction of Allograft Tolerance in the Absence of Fas-Mediated Apoptosis. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.5.2500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Using certain immunosuppressive regimens, IL-2 knockout (KO) mice, in contrast to wild-type (wt) controls, are resistant to the induction of allograft tolerance. The mechanism by which IL-2 regulates allograft tolerance is uncertain. As IL-2 KO mice have a profound defect in Fas-mediated apoptosis, we hypothesized that Fas-mediated apoptosis of alloreactive T cells may be critical in the acquisition of allograft tolerance. To definitively study the role of Fas in the induction of transplantation tolerance, we used Fas mutant B6.MRL-lpr mice as allograft recipients of islet and vascularized cardiac transplants. Alloantigen-stimulated proliferation and apoptosis of Fas-deficient cells were also studied in vivo. Fas mutant B6.MRL-lpr (H-2b) mice rapidly rejected fully MHC-mismatched DBA/2 (H-2d) islet allografts and vascularized cardiac allografts with a tempo that is comparable to wt control mice. Both wt and B6.MRL-lpr mice transplanted with fully MHC-mismatched islet allografts or cardiac allografts can be readily tolerized by either rapamycin or combined costimulation blockade (CTLA-4Ig plus anti-CD40L mAb). Despite the profound defect of Fas-mediated apoptosis, Fas-deficient T cells can still undergo apoptotic cell death in vivo in response to alloantigen stimulation. Our study suggests that: 1) Fas is not necessarily essential for allograft tolerance, and 2) Fas-mediated apoptosis is not central to the IL-2-dependent mechanism governing the acquisition of allograft tolerance.
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Affiliation(s)
- Xian Chang Li
- *Department of Medicine, Harvard Medical School, Division of Immunology, Beth Israel Deaconess Medical Center, Boston, MA 02215; and
| | - Yongsheng Li
- *Department of Medicine, Harvard Medical School, Division of Immunology, Beth Israel Deaconess Medical Center, Boston, MA 02215; and
| | - Ingrid Dodge
- *Department of Medicine, Harvard Medical School, Division of Immunology, Beth Israel Deaconess Medical Center, Boston, MA 02215; and
| | - Andrew D. Wells
- †Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Xin Xiao Zheng
- *Department of Medicine, Harvard Medical School, Division of Immunology, Beth Israel Deaconess Medical Center, Boston, MA 02215; and
| | - Laurence A. Turka
- †Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Terry B. Strom
- *Department of Medicine, Harvard Medical School, Division of Immunology, Beth Israel Deaconess Medical Center, Boston, MA 02215; and
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