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Biomedical subjects

A Radbruch

Publications and source records attributed to A Radbruch.

At least 37 records · Page 2Linked to original sources
PubMed2001

Regulation and function of T1/ST2 expression on CD4+ T cells: induction of type 2 cytokine production by T1/ST2 cross-linking.

The orphan receptor T1/ST2, a member of the IL-1R family, is preferentially expressed on the surface of murine Th2 cells. In this study, we analyzed the kinetics and function of T1/ST2 expression on Th2 cells in vitro. Whereas naive CD4(+) cells did not express T1/ST2, most CD4(+) cells became T1/ST2(+) upon repeated antigenic stimulation under Th2-polarizing conditions. Flow cytometric analyses revealed that the kinetics of T1/ST2 expression on Th2 cells was delayed compared with the kinetics of type 2 cytokine production. Exogenous IL-6, IL-5, IL-1, and TNF-alpha enhanced the expression of T1/ST2 on Th2 cells, and IL-6 was by far most effective in this regard. However, the expression of T1/ST2 did not depend on the presence of IL-6 and was also detected in IL-6-deficient mice. Most important, cross-linking of T1/ST2 provided a costimulatory signal for Th2 but not Th1 cells and directly induced proliferation and type 2 cytokine production. Thus, T1/ST2 is not only a Th2 cell marker but also plays an important role in the activation of Th2 cells.

Animals↗
PubMed2001

Inflamed kidneys of NZB / W mice are a major site for the homeostasis of plasma cells.

(NZB x NZW)F1 (NZB / W) mice develop a disease similar to human systemic lupus erythematosus (SLE), including autoantibody production, hypergammaglobulinaemia and inflammation of the kidneys. It is known that large numbers of lymphocytes infiltrate the kidneys of these mice. Here, we compare the roles of bone marrow, spleen and inflamed kidneys of NZB / W mice in the activation of B cells and the persistence of antibody-secreting cells (ASC). ASC are present in the kidneys of NZB / W mice with full-blown disease, as many as in the spleen and bone marrow. The specificity of the ASC in the inflamed kidneys is not restricted to self-antigens. After immunization of NZB / W mice with ovalbumin (OVA) the OVA-specific ASC are found initially in the spleen. Weeks later, OVA-specific ASC are found in high numbers in the bone marrow and the kidneys of these mice, but no longer in the spleen. As determined by FACS, B cells with a germinal center phenotype (B220(+) / PNA(+)) are found only in very low numbers in the kidneys, but in high numbers in the spleen of NZB / W mice. Germinal centers could not be detected in the kidneys, but in the spleen, and plasma cells appear to be scattered over the tissue. These data suggest that in autoimmune NZB / W mice, plasma cells generated in immune reactions of secondary lymphoid organs, later accumulate and persist in the inflamed kidneys, were they enhance the local concentrations of Ab and immunocomplexes. These experiments identify the inflamed kidneys of NZB / W mice as a site of prime relevance for the homeostasis of plasma cells, irrespective of their specificity.

Animals↗
PubMed2001

Nucleotide sequence and restriction fragment length polymorphisms of the equine Cvarepsilon gene.

IgE is the dominant immunoglobulin isotype involved in type I hypersensitivities in mammals. The heavy chain constant region domains of equine IgE are encoded by a single gene, the Cvarepsilon gene. By restriction analysis of cDNA from 15 unrelated horses, we have now identified two Cvarepsilon alleles, characterised by a Sma I restriction fragment length polymorphism, which we designated Cvarepsilon(a) and Cvarepsilon(b). Sequence analysis of both, Cvarepsilon(a) and Cvarepsilon(b) cDNA, showed in addition two single base exchanges resulting in two amino acid substitutions. Both sequences have only 95.9% homology of the coding region sequence with the published equine Cvarepsilon sequence, which could represent a third haplotype. Polymorphism of the IgE heavy chain constant region gene, as described here, might well impose genetic variability on the effector functions of equine IgE predisposition to allergic diseases in horses.

Alleles↗
PubMed2001

Regulation of expression of IL-4 alleles: analysis using a chimeric GFP/IL-4 gene.

CD4 cells from mice heterozygous for an IL-4 and a GFP/IL-4 gene frequently express a single allele. Analysis of IL-4 or GFP production by cells from recently primed Th2 cells indicates that essentially all are competent to transcribe either allele but have a low probability of doing so. By contrast, long-term Th2 clones show distinct and heritable ratios in the proportion of cells that express IL-4 or GFP. We conclude that in the course of Th2 priming an early efficient event renders both alleles capable of being inefficiently transcribed; a second, less frequent event occurs that renders one allele more competent, accounting for the differential expression of IL-4 and GFP in different clones.

Alleles↗
PubMed2001

Cardiac death after autologous stem cell transplantation (ASCT) for treatment of systemic sclerosis (SSc): no evidence for cyclophosphamide-induced cardiomyopathy.

In patients with systemic sclerosis (SSc) treatment-related mortality after autologous stem cell transplantation (ASCT) appears to be increased as compared to patients with hematological malignancies. In our phase I/II study on ASCT in autoimmune diseases a patient with SSc died on day 2 after ASCT. Here we report the results of the autopsy which revealed advanced pulmonary and cardiac fibrosis as the most probable cause of death. In spite of detailed technical examination before enrollment, the cardiopulmonary function tests did not reflect the advanced stage of the disease. We conclude that in selected patients with SSc, biopsies should be performed to reduce mortality after ASCT.

Cardiomyopathies↗
PubMed2001

Class switch recombination was specifically targeted to immunoglobulin (Ig)G4 or IgA in Hodgkin's disease-derived cell lines.

In T cell-dependent immune responses, class switch recombination occurs in germinal centres. There is now evidence that Hodgkin/Reed-Sternberg cells are derived from germinal centre B cells. Cytokines specifically determine the direction of class switching, i.e the isotype of the new antibodies. We performed restriction analyses and polymerase chain reaction on the immunoglobulin heavy chain loci for five Hodgkin's disease-derived B-cell lines and one Hodgkin's disease-derived T-cell line in order to analyse class switch recombination. In all the B-cell lines, class switch recombination had been targeted to Calpha4 or Calpha1/2. This showed that cell-line precursors had undergone class switching, probably under the influence of TH2 or TH3 cell-derived cytokines. Deletions comprising several constant region genes were observed in cell lines L428, L1236, L591 and KMH2. Karyotype analyses of two of these revealed translocational breakpoints within the immunoglobulin heavy chain gene locus. Our data support the view that a chromosomal instability may occur during class switch recombination in Hodgkin/Reed-Sternberg cells causing chromosomal breaks. Thus, as in other germinal centre B cell-derived lymphomas, the immunoglobulin gene locus may be frequently involved in structural chromosomal aberrations in Hodgkin's disease.

Blotting, Southern↗
PubMed2001

Low T cell production of TNFalpha and IFNgamma in ankylosing spondylitis: its relation to HLA-B27 and influence of the TNF-308 gene polymorphism.

OBJECTIVE: To test the hypothesis that ankylosing spondylitis (AS) is a T helper cell type 2 polarised disease by quantifying the T cell cytokines interferon gamma (IFNgamma), interleukin 4 (IL4), tumour necrosis factor alpha (TNFalpha), and IL10 at the single cell level in patients with AS in comparison with healthy HLA-B27 negative and HLA-B27 positive controls. METHODS: Peripheral blood mononuclear cells from 65 subjects (25 HLA-B27 positive patients with active AS, 18 healthy HLA-B27 positive controls, and 22 healthy HLA-B27 negative controls) were stimulated with phorbol myristate acetate/ionomycin for six hours, surface stained for CD3 and CD8, intracellularly stained for the cytokines IFNgamma, TNFalpha, IL4, and IL10, and analysed by flow cytometry. TNFalpha production was related to the genotype of the TNFalpha promoter at the -308 and -238 polymorphisms. RESULTS: In peripheral blood the percentage of TNFalpha+ T cells was significantly lower in HLA-B27 positive patients with AS (median 5.1% for CD4+ T cells) than in healthy HLA-B27 negative controls (median 9.5%; p=0.008). Surprisingly, the percentage of TNFalpha+ T cells was also significantly lower in healthy HLA-B27 positive controls (median 7.48%) than in healthy HLA-B27 negative controls (p=0.034). Furthermore, the percentage of IFNgamma+ T cells was lower in patients with AS and in healthy HLA-B27 positive controls than in healthy HLA-B27 negative controls (p=0.005 and p=0.003, respectively). The percentage of IL10+/CD8+ T cells was higher in patients with AS than in both control groups. In HLA-B27 positive subjects, TNF1/2 heterozygosity at -308 (n=6) was associated with a higher percentage of TNFalpha+ T cells than TNF1/1 homozygosity (n=25; median 9.97% v 5.11% for CD4+ T cells; p=0.017). In contrast, in HLA-B27 negative controls (n=18) there was no such genotype/phenotype correlation (median 9.4% v 10.6%). CONCLUSIONS: The lower T cell production of TNFalpha and IFNgamma shown at the single cell level in HLA-B27 positive patients with AS and healthy HLA-B27 positive controls may contribute to the increased susceptibility of HLA-B27 positive subjects to develop AS. Preliminary genotype-phenotype correlations suggest that in HLA-B27 positive subjects TNF2 at -308 or a linked gene results in higher TNFalpha production and, therefore, might be a marker for a protective haplotype.

Adult↗
PubMed2000

Disturbed peripheral B lymphocyte homeostasis in systemic lupus erythematosus.

In patients with active systemic lupus erythematosus (SLE), a marked B lymphocytopenia was identified that affected CD19(+)/CD27(-) naive B cells more than CD19(+)/CD27(+) memory B cells, leading to a relative predominance of CD27-expressing peripheral B cells. CD27(high)/CD38(+)/CD19(dim)/surface Ig(low)/CD20(-)/CD138(+) plasma cells were found at high frequencies in active but not inactive SLE patients. Upon immunosuppressive therapy, CD27(high) plasma cells and naive CD27(-) B cells were markedly decreased in the peripheral blood. Mutational analysis of V gene rearrangements of individual B cells confirmed that CD27(+) B cells coexpressing IgD were memory B cells preferentially using V(H)3 family members with multiple somatic mutations. CD27(high) plasma cells showed a similar degree of somatic hypermutation, but preferentially employed V(H)4 family members. These results indicate that there are profound abnormalities in the various B cell compartments in SLE that respond differently to immunosuppressive therapy.

ADP-ribosyl Cyclase↗
PubMed2000

Transfer of IFNgamma-depleted CD4(+) T cells together with CD8(+) T cells leads to rejection of murine kidney sarcoma in mice.

In the murine kidney sarcoma, vaccination with the tumor-specific large T antigen induces protective immunity against the tumor. Immunity is dependent both on CD8(+) cytotoxic T cells and on CD4(+) T-helper cells. We analyzed whether the cytokine phenotype of induced CD4(+) T-effector cells might determine whether or not the tumor is successfully rejected. By intracytoplasmic staining of CD4(+) cells, IFNgamma-producing (Th1), IL-4-producing (Th2), and IL-10-expressing cells could be identified in vaccinated and non-vaccinated animals responding to tumor growth. Vaccinated mice rejecting the tumor showed an increase in the percentage of IL-4-producing (Th2) cells. In contrast, in non-vaccinated mice succumbing to the tumor, the immunosuppressive IL-10-producing cells became more abundant and the frequency of IFNgamma-expressing cells dropped at later time points. Yet, dominance by either a Th1 or a Th2 response could not be observed. To further clarify the relevance of these subsets, Th1 cells were enriched by cell sorting according to IFNgamma surface expression. Enriched Th1 and depleted cells, mainly consisting of the Th2 phenotype, were transferred together with CD8(+) T cells. Surprisingly, immunity could be transferred either with Th1 or Th2 cells, but Th2 cells were slightly more efficient. This suggests that, at least in the effector phase, a Th1 phenotype is not crucial for the rejection. Our findings support the view that the Th1/Th2 dichotomy is not central in T-cell-mediated tumor rejection.

Animals↗
PubMed2000

Autologous stem-cell transplantation in refractory autoimmune diseases after in vivo immunoablation and ex vivo depletion of mononuclear cells.

Autoimmune diseases that are resistant to conventional treatment cause severe morbidity and even mortality. In the present study we demonstrate that complete remissions can be achieved in refractory polychondritis and systemic lupus erythematosus (SLE), even at advanced stage, with the use of autologous stem-cell transplantation (SCT). Remissions persisted after reconstitution of the immune system. In the treatment of advanced systemic sclerosis (SSc), stable disease may be achieved with autologous SCT.

Adult↗
PubMed2000

Impact of in utero Th2 immunity on T cell deviation and subsequent immediate-type hypersensitivity in the neonate.

It was the aim of this study to analyze the impact of maternal Th2 immune responses on onset and subsequent development of allergen-specific immunity and immediate-type hypersensitivity in early childhood. In a well characterized mouse model of Th2 immunity, BALB / c mice were sensitized to ovalbumin (OVA) before mating followed by allergen aerosol exposure during pregnancy. At the end of pregnancy mice developed allergen-specific Th2 / Th0 immunity and immediate-type hypersensitivity responses to OVA. T cells from these newborns, when restimulated with PMA / ionomycin, demonstrated a lowered capacity to produce IFN-gamma. To assess whether prenatal allergen exposure favors postnatal onset of a Th2-type immune response, these offspring were immunized to a novel antigen by a single injection of beta-lactoglobulin (BLG). In contrast to offspring from non-sensitized mothers, offspring from OVA-sensitized mice showed both higher anti-BLG immunoglobulin titers and higher frequencies of immediate-type skin test responses. Our data suggest that Th2 / Th0 immunity present during pregnancy has a decisive impact on shaping of the Th1 / Th2 T cell profile in the neonate. Furthermore, this effect favors the development of Th2 immune responses, when mice are exposed to a novel antigen during early childhood.

Animals↗
PubMed2000

Analysis of the antigen-specific T cell response in reactive arthritis by flow cytometry.

OBJECTIVE: In reactive arthritis (ReA) a bacteria-specific T cell response to the triggering microbe is detected in synovial fluid (SF), and an impaired Th1 cytokine response has been described. The recent identification of immunodominant bacterial proteins/peptides and new technologies make a more detailed analysis of the immune response possible. The aim of the present study was to use these new techniques to determine the antigen-specific T cell frequency and the cytokine secretion pattern on stimulation with bacteria-derived recombinant proteins in the peripheral blood (PB) and SF from patients with ReA. METHODS: In 3 patients with Chlamydia-induced ReA and 2 patients with Yersinia-induced ReA, the SF T cell response was investigated after stimulation with the Chlamydia-derived proteins major outer membrane protein (MOMP) and heat-shock protein 60 (Hsp60) and the Yersinia-derived proteins 19-kd protein and Hsp60. In 3 of these patients, the PB T cell response was investigated in parallel. T cells were stimulated in whole blood or whole SF with antigen plus anti-CD28 for 6 hours, brefeldin A was added after 2 hours, and cells were fixed and stained with antibodies against the surface markers CD4 and CD69 and against the cytokines interferon-gamma (IFNgamma), tumor necrosis factor alpha, interleukin-10 (IL-10), and IL-4. Positive cells were quantified by flow cytometry. RESULTS: In the 3 patients with Chlamydia-induced ReA, the antigen-specific T cell frequency (percentage of IFNgamma CD69 double-positive CD4+ T cells) in response to MOMP (mean +/- SD 1.2 +/- 1.38%) and to Hsp60 (1.21 +/- 1.45%) in SF was about the same. In the 2 patients with Yersinia-induced ReA, the mean +/- SD frequency was 0.66 +/- 0.36% in response to the Hsp60 and 03% +/- 0.22 in response to the 19-kd protein. In the 3 patients whose PB was evaluated, the corresponding T cell response was > or =10 times lower. In 2 patients with Chlamydia-induced ReA, antigen-specific IL-10-positive CD4+ T cells were detected in 0.10-0.23% of the CD4+ T cell subpopulation. CONCLUSION: The frequency of antigen-specific T cells to Chlamydia- and Yersinia-derived antigens in the SF of ReA patients is between 1:200 and 1:50. Both the chlamydial Hsp60 and MOMP are dominant T cell antigens in Chlamydia-induced ReA. In patients with Chlamydia-induced ReA, we detected antigen-specific IL-10 secretion, which might mediate an inhibition of effective bacterial clearance.

Adult↗
PubMed2000

Stat6-independent GATA-3 autoactivation directs IL-4-independent Th2 development and commitment.

The initial source of IL-4-inducing Th2 development and the mechanism of stable Th2 commitment remain obscure. We found the reduced level of IL-4 production in Stat6-deficient T cells to be significantly higher than in Th1 controls. Using a novel cell surface affinity matrix technique, we found that IL-4-secreting Stat6-deficient T cells stably expressed GATA-3 and Th2 phenotype. Introducing GATA-3 into Stat6-deficient T cells completely restored Th2 development, inducing c-Maf, Th2-specific DNase I hypersensitive sites in the IL-4 locus, and Th2 cytokine expression. The fact that GATA-3 fully reconstitutes Th2 development in Stat6-deficient T cells indicates it is a master switch in Th2 development. Finally, GATA-3 exerts Stat6-independent autoactivation, creating a feedback pathway stabilizing Th2 commitment.

Animals↗
PubMed2000

Response to methotrexate in early rheumatoid arthritis is associated with a decrease of T cell derived tumour necrosis factor alpha, increase of interleukin 10, and predicted by the initial concentration of interleukin 4.

OBJECTIVE: This study was performed to assess whether there is any change in the T cell cytokine pattern in early rheumatoid arthritis (RA) patients treated with methotrexate (MTX) and whether the lymphocytic cytokine pattern correlates with disease activity. METHODS: Eight patients with RA (disease duration < six months) were studied serially before, after three, and after six to nine months of treatment with MTX for the cytokines tumour necrosis factor alpha (TNFalpha), interferon gamma (IFNgamma), interleukin 4 (IL4) and interleukin 10 (IL10) by intracellular staining of T cells derived from peripheral blood. Response to treatment was assessed by the modified disease activitiy score. RESULTS: The clincial response was accompanied by a significant decrease of TNFalpha positive CD4(+) T cells from a median of 8.53% (interquartile range 5.83-10.91%) before treatment to 6.17% (2.15-6.81%) after six to nine months of treatment (p=0.021). Inversely, IL10 positive T cells increased from a median of 0.65% (interquartile range 0.6-0.93%) to a median of 1. 3% (1.22%-1.58%) after six to nine months of treatment (p=0.009). No significant change in the percentage of INFgamma positive T cells and a small decrease of IL4 positive T cells during treatment were observed. The percentage of IL4 positive CD4(+) T cells before treatment correlated with disease activity after six to nine months (r= -0.7066; p=0.05). CONCLUSIONS: During treatment of RA with MTX the percentage of TNFalpha producing T cells decreases whereas that of IL10 producing T cells increases. This may affect macrophage activation and, therefore, may represent a regulatory mechanism relevant to disease remission. Furthermore, the percentage of IL4 positive CD4(+) T cells at disease onset may be a useful prognostic marker.

Antirheumatic Agents↗