Strain-Dependent Migration of CD4 and CD8 Lymphocyte Subsets to Lymph Nodes in NOD (Nonobese Diabetic) and Control Mice

Subpopulations of lymphoid cells were compared with respect to their ability to migrate into peripheral lymphoid organs of nonobese diabetic (NOD) mice and various strains of control mice. In short-term, in vivo homing studies, no major differences in the pattern of homing of B and T cells were observed among all mouse strains studied. On the other hand, CD4 cells localized consistently more efficiently than CD8 cells in both PP and LN of adult NOD and BALB/c mice, whereas both populations migrated roughly equivalently in LN of adult DBA/2, CBA, and C57BL/6 mice. No age-dependent differences in the homing of CD4 and CD8 cells were observed in BALB/c mice. On the contrary, in 2-week-old NOD mice, CD4 and CD8 cells migrated equally well. The preferential entry of CD4 cells in adult NOD and BALB/c did not result from increased blood transit time of CD8 cells. On the other hand, the preferential migration of CD8 cells was observed in the liver, whereas the two T-cell subsets migrated equally well in the lungs. The differences in the homing characteristics of CD4 and CD8 cells among NOD, BALB/c, and C57BL/6 mice were not related to modifications in the level of expression of adhesion molecules such as MEL-14, LFA-1, and Pgp-1

Pancreatic Lymph Nodes Are Required for Priming of β Cell Reactive T Cells in NOD Mice

Nonobese diabetic (NOD) mice develop spontaneous autoimmune diabetes that results from the destruction of insulin secreting β cells by diabetogenic T cells. The time and location of the encounter of autoantigen(s) by naive autoreactive T cells in normal NOD mice are still elusive. To address these issues, we analyzed diabetes development in mice whose spleen or pancreatic lymph nodes (panLNs) had been removed. Excision of panLNs (panLNx) at 3 wk protected mice against insulin autoantibodies (IAAs), insulitis, and diabetes development almost completely, but had no effect when performed at 10 wk. The protection afforded by panLNx at weaning was not due to modifications of the immune system, the absence of autoreactive T cells, or the increase in the potency of regulatory T cells. That panLNs are dispensable during adult life was confirmed by the capacity of 10-wk-old panLNx irradiated recipients to develop diabetes upon transfer of diabetogenic T cells. In contrast, splenectomy had no effect at any age. Partial excision of mesenteric LN at 3 wk did not prevent accelerated diabetes by cyclophosphamide as panLNx did. Thus, in normal NOD mice, autoreactive T cell initial priming occurs in LNs draining the target organ of the disease from 3 wk of age

The interaction between lipid derivatives of colchicine and tubulin: Consequences of the interaction of the alkaloid with lipid membranes

AbstractColchicine is a potent antimitotic poison which is well known to prevent microtubule assembly by binding tubulin very tightly. Colchicine also possesses anti-inflammatory properties which are not well understood yet. Here we show that colchicine tightly interacts with lipid layers. The physical and biological properties of three different lipid derivatives of colchicine are investigated parallel to those of membrane lipids in the presence of colchicine. Upon insertion in the fatty alkyl chains, colchicine rigidifies the lipid monolayers in a fluid phase and fluidifies rigid monolayers. Similarly X-ray diffraction data show that lecithin–water phases are destabilized by colchicine. In addition, an unexpectedly drastic enhancement of the photoisomerization rate of colchicine into lumicolchicine in the lipid environment is observed and further supports insertion of the alkaloid in membranes. Finally the interaction of colchicine with lipids makes the drug inaccessible to tubulin. The possible in vivo significance of these results is discussed

Analyse de facteurs génétiques impliqués dans le développement du diabète de type 1 chez la souris NOD

Le diabète de type 1 (DT1) est une maladie multifactorielle pour laquelle des facteurs environnementaux associés à un terrain génétique de prédisposition sont responsables de la destruction auto-immune des cellules |3 insulino-sécrétrices par des lymphocytes T. Au locus Iddô du chromosome 6 murin, les allèles NOD confèrent à la lignée témoin NOD (CO) une susceptibilité au DT1 alors que les allèles C3H/HeJ confèrent une protection contre la maladie à la lignée congénique NOD.C3H 6.VHI (lignée 6.YIII). Mes résultats suggèrent que plusieurs facteurs concourent à une meilleure régulation de la réaction auto-immune chez la lignée 6. VTH : (i) une activité suppressive in vivo accrue des cellules T régulatrices, (ii) une diminution de la voie de signalisation TLR1 conduisant à l'altération des signaux de costimulation au niveau des cellules T et à la diminution de l'expression de cytokines pro-inflammatoires par les macrophages, (iii) une altération du développement des cellules iNKT CD4+.Type 1 diabetes (T1D) is a multifactotial disease: some environmental factors in association with susceptible genetic background lead to the destruction of insuline-producing {J cells by autoreactive T cells. NOD alleles at the Idd6 locus (murine chromosome 6) confer susceptibility to T1D whereas C3H/HeJ alleles in NOD genetic background confer resistance to the disease. Our studies of the congenic mouse strain NOD.C3H 6.VTH (strain 6.VHI) showed that some factors are responsible of its diabetes resistance : (i) a higher suppressive function of regulatory T cells, (ii) the downregulation of Tlrl gene expression leads to reduced costimulatory signals on T cells and to the downregulation of pro-inflammatory cytokines genes expression by macrophages. Genetic(s) factor(s) involved in this phenotype localize at the Idd6.3 locus (iii) a two fold reduction of iNKT CD4+ cells subset, restricted to the Idd6.2 locus.PARIS5-BU Méd.Cochin (751142101) / SudocSudocFranceF

The Activity of Immunoregulatory T Cells Mediating Active Tolerance Is Potentiated in Nonobese Diabetic Mice by an IL-4-Based Retroviral Gene Therapy

Splenocytes from nonobese diabetic mice overexpressing murine IL (mIL)-4 upon recombinant retrovirus infection lose their capacity to transfer diabetes to nonobese diabetic-scid recipients. Diabetes appeared in 0-20% of mice injected with mIL-4-transduced cells vs 80-100% of controls injected with beta-galactosidase-transduced cells. Protected mice showed a majority of islets (60%) presenting with noninvasive peri-insulitis at variance with beta-galactosidase controls that exhibited invasive/destructive insulitis. Importantly, in all recipients, the transduced proteins were detected within islet infiltrates. Infiltrating lymphocytes from recipients of mIL-4-transduced cells produced high levels of mIL-4, as assessed by ELISA. In recipients of beta-galactosidase-transduced cells, approximately 60% of TCRalphabeta(+) islet-infiltrating cells expressed beta-galactosidase, as assessed by flow cytometry. The protection from disease transfer is due to a direct effect of mIL-4 gene therapy on immunoregulatory T cells rather than on diabetogenic cells. mIL-4-transduced purified CD62L(-) effector cells or transgenic BDC2.5 diabetogenic T cells still transferred disease efficiently. Conversely, mIL-4 transduction up-regulated the capacity of purified immunoregulatory CD62L(+) cells to inhibit disease transfer. These data open new perspectives for gene therapy in insulin-dependent diabetes using T cells devoid of any intrinsic diabetogenic potential.