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Cytokines of the common‐γ receptor chain (γc) family are crucial for T‐cell differentiation and dysregulation of γc cytokine pathways is involved in the pathogenesis of autoimmune diseases. There is increasing evidence that the availability of the γc receptor (CD132) for the associated receptor chains has implications for T‐cell functions. Here we studied the influence of differential γc expression on the expression of the IL‐2Rα (CD25), the IL‐7Rα (CD127) and the differentiation of activated naïve T cells. We fine‐tuned the regulation of γc expression in human primary naïve T cells by lentiviral transduction using small hairpin (sh)RNAs and γc cDNA. Differential γc levels were then analysed for effects on T‐cell phenotype and function after activation. Differential γc expression markedly affected IL‐2Rα and IL‐7Rα expression on activated naïve T cells. High γc expression (γc‐high) induced significantly higher expression of IL‐2Rα and re‐expression of IL‐7Rα after activation. Inhibition of γc caused lower IL‐2Rα/IL‐7Rα expression and impaired proliferation of activated naïve T cells. In contrast, γc‐high T cells secreted significantly higher concentrations of effector cytokines (i.e., IFN‐γ, IL‐6) and showed higher cytokine‐receptor induced STAT5 phosphorylation during initial stages as well as persistently higher pSTAT1 and pSTAT3 levels after activation. Finally, accelerated transition towards a CD45RO expressing effector/memory phenotype was seen especially for CD4+ γc‐high naïve T cells. These results suggested that high expression of γc promotes expression of IL‐2Rα and IL‐7Rα on activated naïve T cells with significant effects on differentiation and effector cytokine expression. [ABSTRACT FROM AUTHOR]

Host immune response is key for protection in tuberculosis, but the causative agent, Mycobacterium (M.) tuberculosis, manages to survive despite immune surveillance. Key mechanisms of immune protection have been identified, but the role of immunopathology in the peripheral blood of tuberculosis patients remains unclear. Tuberculosis immunopathology in the blood is characterised by patterns of immunosuppression and hyperinflammation. These seemingly contradictory findings and the pronounced heterogeneity made it difficult to interpret the results from previous studies and to derive implications of immunopathology. However, novel approaches based on comprehensive data analyses and revitalisation of an ancient plasma milieu in vitro assay connected inflammation with immunosuppressive factors in tuberculosis. Moreover, interrelations between the aberrant plasma milieu and immune cell pathology were observed. This review provides an overview of studies on changes in plasma milieu and discusses recent findings linking plasma factors to T‐cell and monocyte/macrophage pathology in pulmonary tuberculosis patients. [ABSTRACT FROM AUTHOR]

Background Doxycycline is used for treatment of Mansonella perstans infection. Immune modulatory effects of both M. perstans and doxycycline have been described but long-term implications on host immune response are not defined. Here we determined multiple immune parameters of M. perstans– infected individuals before and after doxycycline treatment to characterize doxycycline effects on host T-cell immunity. Methods Immune characterization of doxycycline-treated M. perstans– infected individuals was performed as part of an open-label randomized clinical trial. Immune cell population phenotyping by flow cytometry and functional in vitro T-cell assays were performed at baseline, 6 months, and "long term" (18–24 months) after treatment start. Treatment efficacy, based on peripheral blood microfilaria (mf) burden, was correlated with immune parameters and effects on immune response against concomitant Mycobacterium tuberculosis infection were determined. Results Immune population phenotyping indicated changes in functional T-cell responses after doxycycline treatment. Constitutive and superantigen-induced T-cell activation and polarization towards T-helper type (TH) 1 phenotype at baseline declined after doxycycline treatment, whereas low proportions of TH17 and TH1* cells at baseline increased significantly at follow-up. In accordance, long-term decline in antigen-specific TH1 responses against concomitant M. tuberculosis infection was seen. Notably, only TH17 and TH1* changes after 6 months and TH17 at baseline were negatively correlated with M. perstans microfilaria burden or reduction, whereas long-term changes were not associated with treatment efficacy. Conclusions We found long-term immune modulatory effects of doxycycline treatment leading to decreased constitutive T-cell activation, polarization towards TH17/TH1*, and impaired immune response against concomitant M. tuberculosis infection. [ABSTRACT FROM AUTHOR]

Different lymphocyte subsets are involved in autoimmune pathogenesis of type 1 diabetes (T1D). Previous studies suggested a role of CD5‐expressing T and B cells including rare unconventional lymphocytes with combined T‐ and B‐cell features [dual expressing (DE) cells]. We performed algorithm‐supported multiparameter flow cytometry and quantitative PCR to investigate immune cell subsets and DE cells in children with T1D (n = 20) and matched controls (n = 20). Comparisons of conventional immune cells detected increased proportions of CD3+ T cells in T1D patients, whereas CD19+ B‐cell proportions were comparable to controls. Self‐organizing maps for flow cytometry analyses (FlowSOM) showed highly similar CD5‐expressing B‐cell subsets and no differences for DE cells were detected between the study groups by flow cytometry or specific quantitative PCR. Notably, differences in CD8+ T cells were indicated by FlowSOM and similarity‐based t‐distributed stochastic neighbor embedding (tSNE) analyses. Study group comparisons confirmed significantly reduced CD8+ T‐cell proportions with moderate or low CD5 expression in T1D patients. Finally, in vitro experiments showed stable CD5 expression differences of CD8+ T cells after T‐cell activation, cytokine stimulation and culture. We observed differences of T‐cell coreceptor CD5 expression in T1D patients with potential relevance for immune regulation of CD8+ T‐cell activation. [ABSTRACT FROM AUTHOR]

Background and Aim: The hepatokine fetuin A is upregulated in the metabolic syndrome and in type 2 diabetes (T2D), while its role in adolescent type 1 diabetes (T1D) is unclear. We assessed the relationship between circulating fetuin A levels and metabolic control, comorbidities, and complications in adolescent T1D patients. Methods: We studied the relationship between serum fetuin A and clinical diabetes-related data from the DPV registry (Diabetes-Pa­tienten-Verlaufsdokumentation) in 172 adolescent T1D patients with early-onset (<5 years) long-standing (>10 years) T1D. Fetuin A levels were further compared between adolescent T1D and T2D patients. Results: Serum fetuin A levels in T1D patients (mean 0.267 ± 0.043 g/L) did not correlate with age, diabetes duration, gender, body mass index (BMI), glycated hemoglobin, serum lipid levels, blood pressure, celiac or thyroid disease, nephropathy, or retinopathy. An association of fetuin A levels with insulin requirements was only evident within the subgroup of overweight T1D patients (rs = 0.439, p = 0.028, n = 25, BMI >90th percentile), disappearing after adjustment for multiple testing. Adolescent T1D patients showed distinctly lower fetuin A levels than patients with T2D (p ≤ 0.001). Conclusion: Overall, we did not observe a clinically relevant association of fetuin A levels with surrogate parameters for insulin sensitivity in our juvenile T1D cohort. A correlation with insulin requirements was detectable in overweight patients only. We hypothesize that multiple factors, such as obesity, puberty, inadequate metabolic control, and hepatic steatosis, have to add up before a clinically relevant effect of fetuin A on insulin sensitivity becomes evident. [ABSTRACT FROM AUTHOR]

Aberrantly activated CD4+ T memory cells play a central role in the development of type-1-diabetes. Interleukin-7 promotes generation of autoimmune memory T cells and increased Interleukin-7 availability is associated with type-1-diabetes susceptibility. T-cell-mediated immune pathology at onset of type-1-diabetes is well defined, but characteristics of long-term symptomatic disease stages remain largely elusive. In the present study, memory CD4+ T-cell activation and cytokine expression as well as sensitivity to Interleukin-7 in vitro were compared between patients with type-1-diabetes at clinical onset (n=25), long-term symptomatic disease (median duration 4.5 years, n=19) and matched healthy controls (n=21). T-cell responses of type-1-diabetes patients were characterized by higher frequencies of cytokine and activation marker expressing CD4+ memory T cells as compared to healthy controls. Notably, correction for individual cytokine expression levels revealed qualitative differences of cytokine profiles characterized by significantly increased TNFα and decreased IL-2-expressing T-cell proportions in long-term type-1-diabetes patients. IL-7-mediated T-cell co-stimulation induced quantitative and qualitative cytokine expression differences highly similar to type-1-diabetes-specific profiles. In addition, CD4+ memory T cells from children with long-term type-1-diabetes were more sensitive to in vitro IL-7 co-stimulation. Global transcriptome analysis revealed IL-7 induced expression differences of CD4+ T cells, including increased IL-2R expression and effects on subsequent T-cell receptor activation. We conclude that long-term symptomatic type-1-diabetes patients differed in memory T-cell cytokine profiles and Interleukin-7 co-stimulation. Regulation of IL-2 expression and sensitivity are affected with possible consequences for disease course and severity at long-term type-1-diabetes stages. [ABSTRACT FROM AUTHOR]

In this study, we have investigated the contribution of oligodendrocytic connexin47 (Cx47) and astrocytic Cx30 to panglial gap junctional networks as well as myelin maintenance and function by deletion of both connexin coding DNAs in mice. Biocytin injections revealed complete disruption of oligodendrocyte-to-astrocyte coupling in the white matter of 10- to 15-d-old Cx30/Cx47 double-deficient mice, while oligodendrocyte-to-oligodendrocyte coupling was maintained. There were no quantitative differences regarding cellular networks in acute brain slices obtained from Cx30/Cx47 double-null mice and control littermates, probably caused by the upregulation of oligodendrocytic Cx32 in Cx30/Cx47 double-deficient mice. We observed early onset myelin pathology, and ∼40% of Cx30/Cx47 doubledeficient animals died within 42 to 90 d after birth, accompanied by severe motor impairments. Histological and ultrastructural analyses revealed severe vacuolization and myelination defects in all white matter tracts of the CNS. Furthermore, Cx30/Cx47 double-deficient mice exhibited a decreased number of oligodendrocytes, severe astrogliosis, and microglial activation in white matter tracts. Although less affected concerning motor impairment, surviving double-knock-out (KO) mice showed behavioral alterations in the open field and in the rotarod task. Vacuole formation and thinner myelin sheaths were evident also with adult surviving double-KO mice. Since interastrocytic coupling due to Cx43 expression and interoligodendrocytic coupling because of Cx32 expression are still maintained, Cx30/Cx47 double-deficient mice demonstrate the functional role of both connexins for interastrocytic, interoligodendrocytic, and panglial coupling, and show that both connexins are required for maintenance of myelin. [ABSTRACT FROM AUTHOR]

Background: Impaired regulatory T cell immunity plays a central role in the development of type 1 diabetes (T1D). Interleukin-2 receptor (IL-2R) signaling is essential for regulatory T cells (TREG), and cytokine-inducible SH2-containing protein (CIS) regulates IL-2R signaling as a feedback inhibitor. Previous studies identified association of CISH promoter region single nucleotide polymorphisms (SNPs) with susceptibility to infectious diseases.Methods: Here we analyzed allele frequencies of three CISH SNPs (i.e., rs809451, rs414171, rs2239751) in a study of T1D patients (n = 260, onset age < 5 years, duration > 10 years). Minor allele frequencies were compared to a control cohort of the 1000 Genomes Project. Assigned haplotypes were determined for effects on T1D manifestation and severity. Finally, the CISH haplotype influence on cytokine signaling and function was explored in T cells from healthy donors.Results: We detected similar minor allele frequencies between T1D patients and the control cohort. T1D onset age, residual serum C-peptide level, and insulin requirement were comparable between different haplotypes. Only minor differences between the haplotypes were found for in vitro cytokine (i.e., IL-2, IL-7)-induced CIS mRNA expression. STAT5 phosphorylation was induced by IL-2 or IL-7, but no differences were found between the haplotypes. TREG purified from healthy donors with the two most common haplotypes showed similar capacity to inhibit heterologous effector T cells.Conclusions: This study provides no evidence for an association of CISH promoter SNPs with susceptibility to T1D or severity of disease. In contrast to previous studies, no influence of different haplotypes on CIS mRNA expression or T cell-mediated functions was found. [ABSTRACT FROM AUTHOR]

BCG vaccination affects other diseases beyond tuberculosis by unknown-potentially immunomodulatory-mechanisms. Recent studies have shown that BCG vaccination administered during overt type 1 diabetes (T1D) improved glycemic control and affected immune and metabolic parameters. Here, we comprehensively characterized Ghanaian T1D patients with or without routine neonatal BCG vaccination to identify vaccine-associated alterations. Ghanaian long-term T1D patients ( n = 108) and matched healthy controls ( n = 214) were evaluated for disease-related clinical, metabolic, and immunophenotypic parameters and compared based on their neonatal BCG vaccination status. The majority of study participants were BCG-vaccinated at birth and no differences in vaccination rates were detected between the study groups. Notably, glycemic control metrics, i.e., HbA1c and IDAA1c, showed significantly lower levels in BCG-vaccinated as compared to unvaccinated patients. Immunophenotype comparisons identified higher expression of the T cell activation marker CD25 on CD8 + T cells from BCG-vaccinated T1D patients. Correlation analysis identified a negative correlation between HbA1c levels and CD25 expression on CD8 + T cells. In addition, we observed fractional increases in glycolysis metabolites (phosphoenolpyruvate and 2/3-phosphoglycerate) in BCG-vaccinated T1D patients. These results suggest that neonatal BCG vaccination is associated with better glycemic control and increased activation of CD8 + T cells in T1D patients.

The common gamma chain (γ c ) contributes to the formation of different cytokine receptors [e.g., IL-2 receptor (IL-2R), IL-7R, and IL-15R], which are important for generation of self-reactive T-cells in autoimmune diseases, like in type 1 diabetes (T1D). Whereas, the roles of membrane and soluble IL-2Rα and IL-7Rα variants in T1D disease pathogenesis are well-described, effects of γ c expression and availability for dependent receptors remain elusive. We investigated expression of the γ c and dependent receptors on T-cells and soluble γ c concentrations in serum from patients with T1D ( n = 34) and healthy controls ( n = 27). Effector T-cell cytokines as well as IL-2, IL-7, and IL-15 induced STAT5 phosphorylation were analyzed to determine functional implications of differential γ c expression of CD4 + T-cell subsets classified by t-distributed Stochastic Neighbor Embedding (t-SNE) analyses. We found increased γ c and IL-7Rα expression of CD4 + T-cells from T1D patients as compared to controls. t-SNE analyses assigned differential expression to subsets of memory T-cells co-expressing γ c and IL-7Rα. Whereas, γ c expression was positively correlated with IL-2Rα in memory T-cells from healthy controls, no dependency was found for patients with T1D. Similarly, the effector T-cell cytokine, IL-21, correlated inversely with γ c expression in healthy controls, but not in T1D patients. Finally, T1D patients with high γ c expression had increased proportions of IL-2 sensitive pSTAT5 + effector T-cells. These results indicated aberrantly high γ c expression of T-cells from T1D patients with implications on dependent cytokine receptor signaling and effector T-cell cytokine production.