| 1. |
- Casas, Rosaura, 1954-, et al.
(författare)
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Impaired maturation of monocyte-derived dendritic cells from birch allergic individuals in association with birch-specific immune responses
- 2007
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 66:5, s. 591-598
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Tidskriftsartikel (refereegranskat)abstract
- Optimal activation of T lymphocytes requires a costimulatory signal provided by the interaction of molecules on the surface of T cells with their ligands expressed on dendritic cells (DC). We investigated whether DC differentiated from monocytes from healthy and birch allergic asthmatic individuals and further maturated by stimulation with cat and birch allergens and LPS differ in their phenotypic receptor expression. Similar expression of DC surface markers, including HLA-DR, CD80, CD86, CD83, CD1a and CD11c, was detected in monocyte-derived DC from allergic and healthy individuals. Cells from healthy donors stimulated either antigen showed a similar activation of the CD80 and double CD80/CD86 costimulatory molecules when compared with non-stimulated cells. In the case of cells from allergic individuals, birch allergen was unable to produce the same increased expression of CD80 alone or in combination with CD80/CD86, in comparison with cells stimulated with cat and LPS. Levels of IL-6, IL-8, IL-10, MCP-1/MCAF and MIP-1β were similar in the supernatant of non-stimulated DC from both groups of subjects. By contrast, the spontaneous secretion of IL-12p70 and TNF-α was higher in the supernatant of DC from healthy subjects when compared with that from allergic individuals. Stimulation with birch and LPS resulted in an increased secretion of IL-12p70 in samples from healthy when compared with that in allergic individuals. The results suggest an impaired specific maturation of DC from birch allergic individuals in association with birch-specific immune responses. Lower secretion of IL-12p70 from birch-stimulated DC from allergic individuals suggests that not only maturation, but also the specific Th1 function of these cells seems to be affected in those individuals.
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| 2. |
- Skarsvik, Susanne, 1978-
(författare)
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Aberrancies associated with dendritic cells and T lymphocytes in type 1 diabetes
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The incidence of type 1 diabetes has rapidly increased in the Western world and the age of onset has shifted to younger ages. Type 1 diabetes is a chronic disease caused by destruction of the insulin producing ß-cells in the pancreas leading to severe insulin deficiency. This results in hyperglycaemia and diagnosis of overt type 1 diabetes.The pathogenesis of type 1 diabetes is not fully understood. When diagnosed during childhood, the ß-cell destruction is believed to be caused by autoreactive T cells in the majority of cases. The effect of autoreactive T cells is limited by dendritic cells, which are involved in the induction of tolerance and in regulating T cells. Different subsets of T cells also play a role in regulating immune responses. The activation of autoreactive T cells is believed to be triggered by environmental factors e.g. coxsackievirus B4 and/or dietary factors. The major genetic determinant for type 1 diabetes is associated with the HLA class II genes encoding the HLA molecules on antigen presenting cells.The aim of the present study was to study the maturation of dendritic cells and how T cell reactivity is influenced by genetic and environmental factors in children with type 1 diabetes and/or children with increased genetic risk of developing type 1 diabetes in comparison to healthy children.The maturation of dendritic cells was studied by in vitro differentiation of monocytes into dendritic cells. Our results showed that children with type 1 diabetes and those with genetic risk of type 1 diabetes had a lower percentage of dendritic cells expressing CD11c and HLA-DR in addition to decreased secretion of TNF.The regulation of T cell polarization was investigated in children with type 1 diabetes and in neonates at genetic risk of type 1 diabetes by in vitro polarization of T cells. Children with newly diagnosed and longstanding type 1 diabetes had a lower number of CD4 and CD8 T cells expressing IL-12Rß2-chain and increased secretion of IL-13 from lymphocytes cultured in type 1 cytokine environment in comparison to healthy children. Neonates carrying type 1 diabetes risk associated haplotypes DQ2/DQ8 or DQ8 had a lower percentage of CD4 T cells expressing CCR4, lower mRNA levels of CCR4 and GATA-3 and lower secretion of IL-13 in lymphocytes cultured in type 2 cytokine environment compared to neonates without genetic risk of type 1 diabetes. Furthermore, we found that children with type 1 diabetes had a lower percentage of CD4 and CD8 T cells expressing CCR2, CXCR6 and IL-18R after in vitro stimulation of peripheral blood mononuclear cells with coxsackievirus B4 in comparison to healthy children with and without genetic risk of type 1 diabetes. We also found decreased secretion of IFN-γ and lower levels of Tbet mRNA from peripheral blood mononuclear cells stimulated with coxsackievirus B4 in children with type 1 diabetes compared to healthy children with and without genetic risk of type 1 diabetes.In conclusion, defects in the function of dendritic cells and in the polarization of T cells may contribute to an underlying immunological environment, which allows autoimmune responses to develop and impair the host defence mechanisms against pathogens. Ultimately these immunological aberrancies may lead to development of ß-cell autoimmunity.
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| 3. |
- Skarsvik, Susanne, 1978-, et al.
(författare)
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Aberrant regulation of interleukin-12 receptor β2 chain on type 1 cytokine-stimulated T lymphocytes in type 1 diabetes
- 2005
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Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 114:2, s. 287-293
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Tidskriftsartikel (refereegranskat)abstract
- An aberrant mitogen-induced polarization of peripheral blood T cells has been associated with type 1 diabetes (T1D). We studied, in T1D, type 1 and 2 cytokine-induced expression of the interleukin-12 receptor β2 chain (IL-12Rβ2 chain), which plays a critical role in regulating T-cell polarization. Peripheral blood lymphocytes from children with newly diagnosed T1D (n = 10; mean age 10 years), from children with longstanding T1D (n = 8; mean age 12·9 years) and from healthy children (n = 15; mean age 11·5 years) were stimulated with phytohaemagglutinin (PHA) in a type 1 (IL-12 and anti-IL-4) or a type 2 (IL-4 and anti-IL-12) cytokine environment. Secretion of interferon-γ (IFN-γ), IL-5 and IL-13, as detected by enzyme-linked immunosorbent assay (ELISA), and expression of the IL-12Rβ2 chain on CD4 and CD8 cells by flow cytometry, were analysed. Children with newly diagnosed and longstanding T1D had lower expression levels of the IL-12Rβ2 chain on IL-12Rβ2 chain-positive CD4 T cells (for a type 1 or a type 2 cytokine environment: P = 0·01 and P = 0·002 or P = 0·02 and P = 0·01, respectively) and on IL-12Rβ2 chain-positive CD8 T cells (for a type 1 or a type 2 cytokine environment: P = 0·007 and P = 0·0007 or P = 0·003 and P = 0·01, respectively) when compared to healthy children. A decreased percentage of IL-12Rβ2 chain-expressing CD4 T cells (P = 0·07 and P = 0·03) and CD8 T cells (P = 0·004 and P = 0·01) and increased secretion of IL-13 (P = 0·006 and P = 0·04) in a type 1 cytokine environment was seen in both groups of patients. Peripheral blood T cells from patients with both newly diagnosed and longstanding T1D showed poor polarization towards type 1 cells.
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| 4. |
- Skarsvik, Susanne, 1978-, et al.
(författare)
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Decreased in vitro type 1 immune response against coxsackie virus B4 in children with type 1 diabetes
- 2006
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 55:4, s. 996-1003
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Tidskriftsartikel (refereegranskat)abstract
- Enteroviruses, particularly Coxsackie virus B4 (CVB4), are considered to be involved in the pathogenesis of type 1 diabetes. We wanted to compare the characteristics of T-cell immune response to CVB4 in children with type 1 diabetes and healthy children with and without HLA risk-associated haplotypes (HLA-DR3-DQ2 or HLA-DR4-DQ8) for type 1 diabetes. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured with CVB4 and analyzed for cytokine and chemokine receptors by flow cytometry and for expression of transcription factors Tbet and GATA-3 by RT-PCR and Western blot. Culture supernatants were analyzed for secretion of γ-interferon (IFN-γ). In children with type 1 diabetes, a decreased percentage of T-cells expressed CCR2, CXCR6, interleukin (IL)-18R, and IL-12Rβ2-chain after in vitro stimulation with CVB4 in comparison with healthy children with or without HLA risk genotype. Moreover, we found that children with type 1 diabetes had decreased IFN-γ secretion and expression of Tbet, both on mRNA and protein level, in CVB4-stimulated PBMCs. Accordingly, children with type 1 diabetes show an impaired type 1 immune response against CVB4 compared with healthy children. This may lead to a delayed clearance of the virus and, at least partly, explain why children with type 1 diabetes may be more prone to CVB4 infections and related complications, such as β-cell damage.
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| 5. |
- Skarsvik, Susanne, 1978-, et al.
(författare)
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Poor in vitro maturation and pro-inflammatory cytokine response of dendritic cells in children at genetic risk of type 1 diabetes
- 2004
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 60:6, s. 647-652
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Tidskriftsartikel (refereegranskat)abstract
- Type 1 diabetes (T1D) has been associated with an aberrant maturation of dendritic cells (DC). We studied the maturation of monocyte-derived DC in children with newly diagnosed T1D and in healthy children with genetic risk for T1D. Peripheral blood monocytes from children with newly diagnosed T1D (n = 12; mean age 13.2 years), children with human leukocyte antigen (HLA)-risk genotype of T1D (n = 7; mean age 12.7 years) and healthy children (n = 14; mean age 11.2 years) were in vitro differentiated into DC. Expression of HLA-DR, CD80/86 and CD11c and secretion of interleukin (IL)-12, tumor necrosis factor (TNF)-α, IL-6 and IL-10 were measured using flow cytometry. Lower percentage of DC expressed CD11c and HLA-DR, and decreased production of TNF-α was found in children with newly diagnosed T1D and in children at genetic risk when compared to healthy children. Children with risk genotype also had decreased IL-12 production by DC. Children with T1D and children at genetic risk of T1D appear to have similar aberrancies in the maturation of DC, which may predispose to β-cell autoimmunity.
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