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ObjectiveA pilot study suggested that combination therapy with low-dose anti-thymocyte globulin (ATG) and pegylated granulocyte colony-stimulating factor (GCSF) preserves C-peptide in established type 1 diabetes (T1D) (duration 4 months to 2 years). We hypothesized that 1) low-dose ATG/GCSF or 2) low-dose ATG alone would slow the decline of β-cell function in patients with new-onset T1D (duration

We previously demonstrated that a spontaneous Th1 response against glutamate decarboxylase (GAD65) arises in NOD mice at four weeks in age and subsequently T cell autoimmunity spreads both intramolecularly and intermolecularly. Induction of passive tolerance to GAD65, through inactivation of reactive T cells before the onset of autoimmunity, prevented determinant spreading and the development of insulin-dependent diabetes mellitus (IDDM). Here, we examined whether an alternative strategy, designed to induce active tolerance via the engagement of Th2 immune responses to GAD65, before the spontaneous onset of autoimmunity, could inhibit the cascade of Th1 responses that lead to IDDM. We observed that a single intranasal administration of GAD65 peptides to 2-3-wk-old NOD mice induced high levels of IgG1 antibodies to GAD65. GAD65 peptide treated mice displayed greatly reduced IFN gamma responses and increased IL-5 responses to GAD65, confirming the diversion of the spontaneous GAD65 Th1 response toward a Th2 phenotype. Consistent with the induction of an active tolerance mechanism, splenic CD4+ (but not CD8+) T cells from GAD65 peptide-treated mice, inhibited the adoptive transfer of IDDM to NOD-scid/scid mice. This active mechanism not only inhibited the development of proliferative T cell responses to GAD65, it also limited the expansion of autoreactive T cell responses to other beta cell antigens (i.e., determinant spreading). Finally, GAD65 peptide treatment reduced insulitis and long-term IDDM incidence. Collectively, these data suggest that the nasal administration of GAD65 peptides induces a Th2 cell response that inhibits the spontaneous development of autoreactive Th1 responses and the progression of beta cell autoimmunity in NOD mice.

Crohn's disease (CD) is a chronic inflammatory condition of the human gastrointestinal tract whose aetiology remains largely unknown. Dysregulated adaptive immune responses and defective innate immunity both contribute to this process. In this study, we demonstrated that the interleukin (IL)-17A+interferon (IFN)-γ+ and IL-22+IFN-γ+ T cell subsets accumulated specifically in the inflamed terminal ileum of CD patients. These cells had higher expression of Ki-67 and were active cytokine producers. In addition, their proportions within both the IL-17A-producer and IL-22-producer populations were increased significantly. These data suggest that IL-17A+IFN-γ+ and IL-22+IFN-γ+ T cell subsets might represent the pathogenic T helper type 17 (Th17) population in the context of intestinal inflammation for CD patients. In the innate immunity compartment we detected a dramatic alteration of both phenotype and function of the intestinal innate lymphoid cells (ILCs), that play an important role in the maintenance of mucosal homeostasis. In the inflamed gut the frequency of the NKp44-CD117-ILC1s subset was increased significantly, while the frequency of NKp44+ILC3s was reduced. Furthermore, the frequency of human leucocyte antigen D-related (HLA-DR)-expressing-NKp44+ILC3s was also reduced significantly. Interestingly, the decrease in the NKp44+ILC3s population was associated with an increase of pathogenic IL-17A+IFN-γ+ and IL-22+IFN-γ+ T cell subsets in the adaptive compartment. This might suggest a potential link between NKp44+ILC3s and the IL-17A+IFN-γ+ and IL-22+IFN-γ+ T cell subsets in the terminal ileum of CD patients. [ABSTRACT FROM AUTHOR]

The 'hyper-responsive' trait is an increased inflammatory response upon stimulation of innate immune receptors. Our objective was to determine if a hyper-reactive trait is present in a cohort diagnosed with aggressive periodontitis (LAgP). Peripheral blood was collected from 30 LAgP, 10 healthy unrelated, and 10 healthy sibling participants and stimulated with lipopolysaccharide (LPS) from E. coli and P. gingivalis. Cyto/chemokine response profiles were evaluated and analyzed by ANOVA. Elevated levels of pro-inflammatory cyto/chemokines were detected in E. coli and P. gingivalis LPS-stimulated LAgP cultures when compared with those of healthy unrelated control individuals. Periodontally healthy siblings presented with attenuated hyper-inflammatory cyto/chemokine profiles. Regression analysis demonstrated the hyper-reactive trait to be concomitant expression of pro-inflammatory cyto/chemokines and an absence of anti-inflammatory mediator expression. Our findings demonstrate hyper-responsive trait in a LAgP cohort, along with an attenuated hyper-responsiveness in healthy siblings, which can be induced in response to multiple TLR ligations. [ABSTRACT FROM AUTHOR]

Recently, we identified in normally type 1 diabetes-prone NOD/LtJ mice a spontaneous new leptin receptor (LEPR) mutation (designated Lepr(db-5J)) producing juvenile obesity, hyperglycemia, hyperinsulinemia, and hyperleptinemia. This early type 2 diabetes syndrome suppressed intra-islet insulitis and permitted spontaneous diabetes remission. No significant differences in plasma corticosterone, splenic CD4(+) or CD8(+) T-cell percentages, or functions of CD3(+) T-cells in vitro distinguished NOD wild-type from mutant mice. Yet splenocytes from hyperglycemic mutant donors failed to transfer type 1 diabetes into NOD.Rag1(-/-) recipients over a 13-week period, whereas wild-type donor cells did so. This correlated with significantly reduced (P < 0.01) frequencies of insulin and islet-specific glucose-6-phosphatase catalytic subunit-related protein-reactive CD8(+) T-effector clonotypes in mutant mice. Intra-islet insulitis was also significantly suppressed in lethally irradiated NOD-Lepr(db-5J)/Lt recipients reconstituted with wild-type bone marrow (P < 0.001). In contrast, type 1 diabetes eventually developed when mutant marrow was transplanted into irradiated wild-type recipients. Mitogen-induced T-cell blastogenesis was significantly suppressed when splenic T-cells from both NOD/Lt and NOD-Lepr(db-5J)/Lt donors were incubated with irradiated mutant peritoneal exudate cells (P < 0.005). In conclusion, metabolic disturbances elicited by a type 2 diabetes syndrome (insulin and/or leptin resistance, but not hypercorticism) appear to suppress type 1 diabetes development in NOD-Lepr(db-5J)/Lt by inhibiting activation of T-effector cells. [ABSTRACT FROM AUTHOR]

Dendritic cells (DC) represent a potential target for gene therapy. In their ability to process antigens and present them to T cells, DC have been allocated a unique role as initiators of the immune response in both the innate and acquired immunity. Recentin vitrostudies have showed the feasibility of DC transduction with adenoviral recombinants. In cancer therapy, targeting of DC with adenovirus has been proved to be effective in inhibiting tumour growth, as well as in reducing the number of tumour metastases. The aim of our study is to evaluate the feasibility ofin vivotransduction of DC in a murine lymphocyte-rich compartment (thymus) as a potential treatment for acute inflammatory diseases. Nearly 50% of the total thymic DC were transduced with a first-generation adenoviral construct following intrathymic injection, and post-transductional inflammation was neglectable. Transduction of thymic cells with adenoviral recombinants was able to induce the expression of an intracellular protein (β-galactosidase, green fluorescent protein), as well as the secretion of human interleukin-10, within the local compartment. Furthermore, this induction of the latter significantly decreased thymic apoptosis in the applied model of acute bacterial peritonitis (cecal ligation and puncture). [ABSTRACT FROM AUTHOR]

Dendritic cells (DC) isolated from various lymph node (LN) groups of pre-diabetic non-obese diabetic (NOD) (4-20 weeks of age) and age-sex-matched control mice were analysed for their surface antigen phenotype and their ability to cluster lymphocytes. The draining LN of the pancreas (PLN) of 8-week-old NOD mice with active autoimmune disease were significantly enlarged in comparison to the axillary LN of the same NOD mice and the PLN from control mice. NOD DC isolated from PLN and other LN demonstrated classical DC morphology, were highly major histocompatibility complex (MHC) class II antigen positive, and were 50-70% 33D1+ (DC-specific antibody). In an assay for DC-T cell clustering, DC from the PLN of 8-20-week-old NOD formed large clusters (> 10 cells) with PLN cells at a frequency three to 20 times greater than that observed with DC and LN cells from the PLN of 8-week-old control mice, the PLN of 4-week-old NOD mice, and axillary/inguinal LN of 8-week-old NOD mice. Clustered cells were 80% Thy-1.2+ (56% L3T4, 17% Lyt-2+). Specificity of clustering was demonstrated as PLN DC clustered only PLN T cells in the assay; axillary/inguinal (A/I) DC added to PLN LC did not induce clustering nor did PLN DC induce clustering of the A/I population. Cell proliferation in isolated PLN DC/LC clusters was markedly greater than that of A/I clusters and of non-clustered PLN cells. These data demonstrate that DC from the PLN of NOD mice with active autoimmune disease form stable clusters with T cells from the PLN and these clusters are the major source of proliferating I cells in these LN. We hypothesize that PLN DC may play an important role in the autoimmune disease of the NOD mouse. [ABSTRACT FROM AUTHOR]

Abstract Background ATG has been employed to deplete T cells in several immune-mediated conditions. However, whether ATG administration affects naïve and memory T cell differently is largely unknown. The context and purpose of the study In this study, we assessed how murine ATG therapy affected T cell subsets in NOD mice, based on their regulatory and naïve or memory phenotype, as well as its influence on antigen-specific immune responses. Results Peripheral blood CD4+ and CD8+ T cells post-ATG therapy declined to their lowest levels at day 3, while CD4+ T cells returned to normal levels more rapidly than CD8+ T cells. ATG therapy failed to eliminate antigen-primed T cells. CD4+ T cell responses post-ATG therapy skewed to T helper type 2 (Th2) and possibly IL-10-producing T regulatory type 1 (Tr1) cells. Intriguingly, Foxp3+ regulatory T cells (Tregs) were less sensitive to ATG depletion and remained at higher levels following in vivo recovery compared to controls. Of note, the frequency of Foxp3+ Tregs with memory T cell phenotype was significantly increased in ATG-treated animals. Conclusion ATG therapy may modulate antigen-specific immune responses through inducing memory-like regulatory T cells as well as other protective T cells such as Th2 and IL-10-producing Tr1 cells.