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| 2. |
- Colucci, Francesco, et al.
(författare)
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Apoptosis resistance of nonobese diabetic peripheral lymphocytes linked to the Idd5 diabetes susceptibility region
- 1997
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 94:16, s. 8670-8674
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Tidskriftsartikel (refereegranskat)abstract
- Defects in lymphocyte apoptosis may lead to autoimmune disorders and contribute to the pathogenesis of type 1 diabetes. Lymphocytes of nonobese diabetic (NOD) mice, an animal model of autoimmune diabetes, have been found resistant to various apoptosis signals, including the alkylating drug cyclophosphamide. Using an F2 intercross between the apoptosis-resistant NOD mouse and the apoptosis-susceptible C57BL/6 mouse, we define a major locus controlling the apoptosis-resistance phenotype and demonstrate its linkage (logarithm of odds score = 3.9) to a group of medial markers on chromosome 1. The newly defined gene cannot be dissociated from Ctla4 and Cd28 and in fact marks a 20-centimorgan region encompassing Idd5, a previously postulated diabetes susceptibility locus. Interestingly, we find that the CTLA-4 (cytotoxic T lymphocyte-associated antigen 4) and the CD28 costimulatory molecules are defectively expressed in NOD mice, suggesting that one or both of these molecules may be involved in the control of apoptosis resistance and, in turn, in diabetes susceptibility.
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| 3. |
- Colucci, Francesco, et al.
(författare)
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Induction of diabetes in NOD‹–›C57BL/6 embryo aggregation chimeras by cyclophosphamide through preferential depletion of C57BL/6 lymphocytes
- 1996
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Ingår i: Journal of Autoimmunity. - : Elsevier. - 0896-8411 .- 1095-9157. ; 9:4, s. 493-499
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Tidskriftsartikel (refereegranskat)abstract
- The majority of embryo aggregation (EA) mouse chimeras between non-obese diabetic (NOD) mice and C57BL/6 (B6) mice show clear signs of insulitis frequently accompanied by beta-cell destruction. Less than 5% of these chimeras, however, spontaneously progress to autoimmune diabetes, an incidence far lower than observed in NOD mice. The resistance in chimeras can be accounted for by the target organ chimerism and/or the immune system chimerism. To investigate the mechanism(s) controlling diabetes resistance in these mice, we studied a total of 92 NOD<-->B6 EA chimeras that showed overt lymphoid chimerism and treated 34 chimeras with cyclophosphamide (CY), a compound known to precipitate an acute form of insulin-dependent diabetes mellitus (IDDM) in pre-diabetic NOD mice, by interfering with regulatory mechanisms. We found that CY-treated EA chimeras displayed an increase in the NOD:B6 lymphocyte ratio and 32% of them developed diabetes that could be adoptively transferred to irradiated NOD or NOD-rag-2-/- mice. These findings suggest that lymphocyte chimerism rather than beta-cell chimerism accounts for diabetes resistance in NOD<-->B6 EA chimeras and that the susceptibility to CY-induced diabetes may be related to the proportion of NOD versus B6 lymphoid cells.
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| 4. |
- Colucci, Francesco, et al.
(författare)
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Programmed cell death in the pathogenesis of murine IDDM : resistance to apoptosis induced in lymphocytes by cyclophosphamide
- 1996
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Ingår i: Journal of Autoimmunity. - : Elsevier. - 0896-8411 .- 1095-9157. ; 9:2, s. 271-276
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Tidskriftsartikel (refereegranskat)abstract
- The non-obese diabetic (NOD) mouse displays several immune related defects, each of which could potentially contribute to the immunopathogenesis of diabetes that spontaneously develops in these mice. The reported resistance of NOD-lymphocytes to several apoptosis-inducing signals constitutes one such factor. Apoptosis plays a key role in the homeostasis of the immune system, as a means of selecting lymphocyte repertoires both in primary lymphoid organs and in the periphery; distortions in the apoptotic machinery may therefore be hypothesized to be implicated in the pathogenesis of autoimmune disorders. We now report that cyclophosphamide constitutes an apoptosis signal to peripheral lymphocytes and we provide evidence that NOD B cells as well as both CD4 and CD8 T cells display resistance to cyclophosphamide-induced apoptosis. These observations support the notion that apoptosis resistance in NOD mice exists at various levels, and suggest that the CY-sensitive lymphoid population, believed to play an important role in inhibiting the disease in diabetes resistant NOD mice (particularly males), may be controlled by mechanisms that are mediated by apoptosis.
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| 5. |
- Hillörn, Valter, et al.
(författare)
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Aberrant VHGene Utilization in Patients with Established Insulin-Dependent Diabetes Mellitus
- 1997
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Ingår i: Journal of Autoimmunity. - : Elsevier BV. - 0896-8411 .- 1095-9157. ; 10:2, s. 157-163
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Tidskriftsartikel (refereegranskat)abstract
- We have compared the B-lymphocyte repertoire in seven IDDM patients with 12 healthy controls by examining the variable heavy (VH) gene expression. The VHgene representation in the pool of pokeweed mitogen (PWM) stimulated, immunocompetent B cells and in the pool of naturally activated plasma cells (actual repertoire) was analysed by RNA-RNA in situ hybridization. Differences between IDDM patients and normal controls in the relative expression of several VHgene families were observed. In IDDM patients, the VH3 was significantly underrepresented in the PWM stimulated repertoire. In the actual B cell repertoire the VH5 clones were underrepresented among diabetic patients. Moreover, the altered distribution of VHgene usage between the PWM stimulated repertoire and the actual repertoire observed in normal controls was found to be less pronounced in the IDDM patients. This observation suggests a defect in the V-gene directed cellular selection occurring between resting, immunocompetent B cells and naturally activated plasma cells. The possible implication of the observed aberrations in the B cell selection process for the pathogenesis of autoimmunity is discussed.
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