| 11. |
- Sakata, Naoki, et al.
(författare)
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Differential activation and regulation of mitogen activated protein kinases through the antigen receptor and CD40 in human B cells
- 1999
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Ingår i: European Journal of Immunology. - 0014-2980 .- 1521-4141. ; 29:9, s. 2999-3008
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Tidskriftsartikel (refereegranskat)abstract
- In human B cells, antigen receptor ligation and CD40 ligation are known to activate the extracellular-regulated kinases (ERK) and c-Jun N-terminal kinase (JNK) pathways, which in turn regulate many important B cell functions. We previously reported that antigen receptor ligation activated the ERK pathway whereas CD40 ligation activated the JNK/stress-activated protein kinase (SAPK) pathway. Here, we demonstrate that another SAPK, p38/Hog1, is activated by both antigen receptor ligation or CD40 ligation in a human B-lymphoblastoid cell line and tonsillar B cells. Wortmannin, an inhibitor of phosphatidylinositol 3-kinase, partially inhibited ERK2 and p38 activation triggered through the B cell receptor whereas activation of JNK1 and p38 through CD40 was not affected. PD98059, a specific inhibitor of mitogen-activated extracellular response kinase kinase (MEK), significantly inhibited ERK2 activation and partially inhibited p38 activation triggered by anti-IgM antibody treatment, but did not affect CD40-dependent signaling events. In addition, anti-IgM antibody-induced signaling pathways were shown to be PKC-dependent in contrast to the CD40-induced signaling pathways. Thus, the B cell receptor and CD40 recruit the ERK, JNK and p38 pathways by using different upstream effectors.
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| 12. |
- Söderström, Ingegerd, et al.
(författare)
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Altered VH6-D-JH repertoire in human insulin-dependent diabetes mellitus and autoimmune idiopathic thrombocytopenic purpura
- 1999
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Ingår i: European Journal of Immunology. - : Wiley-VCH Verlagsgesellschaft. - 0014-2980 .- 1521-4141. ; 29:9, s. 2853-2862
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Tidskriftsartikel (refereegranskat)abstract
- We have characterized the peripheral B cell repertoire in T cell-mediated insulin-dependent diabetes mellitus (IDMM) and in B cell-mediated autoimmune idiopathic thrombocytopenic purpura (AITP). The VH6-containing repertoire in adult patients with IDDM or AITP and healthy control subjects was investigated by PCR amplification using VH6- and JH-specific primers. Nucleotide sequence analysis of VH6-D-JH rearrangements showed an abnormally high frequency of somatic mutations in non-functional rearrangements from diabetic (3. 58 %) as well as AITP patients (3.18 %), compared to controls (0.4 % and 1.43 %, respectively; p < 0.05). In contrast, the mutation frequency among functional rearrangements was 2.4 - 3 times lower in patients compared to controls ( p < 0.05). Detailed analysis of the VH6 genes carrying mutations showed that the underlying mechanism for this observation is probably different for the two diseases. Analysis of D- and JH gene usage revealed additional deviations from the normal pattern. Taken together, these results suggest defects in the mechanisms controlling selection of the B cell repertoire in patients with IDDM or AITP.
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| 13. |
- Xie, Xiao-Qi, et al.
(författare)
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AML and Ets proteins regulate the I alpha1 germ-line promoter.
- 1999
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Ingår i: European Journal of Immunology. - 0014-2980 .- 1521-4141. ; 29:2, s. 488-498
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Tidskriftsartikel (refereegranskat)abstract
- The immunoglobulin heavy chain (IgH) class switch recombination of B lymphocytes preferentially targets unrearranged IgH genes that have already been rendered transcriptionally active. Transcription of the germ-line IgH genes is controlled by intervening (I) regions upstream of their switch regions. The I alpha1 promoter activates transcription of the human germ-line C alpha1 gene for IgA1 and mediates the transforming growth factor (TGF)-beta1 responsiveness of this locus. Here we show that the I alpha1 promoter contains several binding sites for the AML/PEBP2/CBF family of transcription factors and that AML and Ets proteins are major regulators of the basal and TGF-beta-inducible promoter activity. Our data constitute a starting point for studies to elucidate the molecular mechanism by which TGF-beta regulates IgA production.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Ahlgren, Kerstin M., et al.
(författare)
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Increased IL-17A secretion in response to Candida albicans in autoimmune polyendocrine syndrome type 1 and its animal model
- 2011
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 41:1, s. 235-245
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Tidskriftsartikel (refereegranskat)abstract
- Autoimmune polyendocrine syndrome type 1 (APS-1) is a multiorgan autoimmune disease caused by mutations in the autoimmune regulator (AIRE) gene. Chronic mucocutaneous candidiasis, hypoparathyroidism and adrenal failure are hallmarks of the disease. The critical mechanisms causing chronic mucocutaneous candidiasis in APS-1 patients have not been identified although autoantibodies to cytokines are implicated in the pathogenesis. To investigate whether the Th reactivity to Candida albicans (C. albicans) and other stimuli was altered, we isolated PBMC from APS-1 patients and matched healthy controls. The Th17 pathway was upregulated in response to C. albicans in APS-1 patients, whereas the IL-22 secretion was reduced. Autoantibodies against IL-22, IL-17A and IL-17F were detected in sera from APS-1 patients by immunoprecipitation. In addition, Aire-deficient (Aire(0/0) ) mice were much more susceptible than Aire(+/+) mice to mucosal candidiasis and C. albicans-induced Th17- and Th1-cell responses were increased in Aire(0/0) mice. Thus an excessive IL-17A reactivity towards C. albicans was observed in APS-1 patients and Aire(0/0) mice.
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| 18. |
- Akeus, Paulina, et al.
(författare)
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Regulatory T cells reduce endothelial neutral sphingomyelinase 2 to prevent T-cell migration into tumors
- 2021
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 51:9, s. 2317-2329
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Tidskriftsartikel (refereegranskat)abstract
- Endothelial cells are key regulators of transendothelial migration and their secretion of chemokines and expression of adhesion molecules facilitates lymphocyte entry into tissues. Previously, we demonstrated that Tregs can reduce transendothelial migration of T cells into tumors by decreasing endothelial CXCL10 secretion, but the mechanism by which this occurs is still not known. In this study, we aimed to define how Tregs decrease transendothelial migration into tumors. mRNA sequencing of intestinal tumor endothelial cells from Treg depleted mice identified neutral sphingomyelinase 2 (nSMase2) as a gene downregulated in the presence of Tregs. nSMase2 is expressed in human umbilical vein endothelial cells (HUVECs) and was decreased after coculture with Tregs. Furthermore, blocking of nSMase2 activity in vitro decreased VCAM1, CX3CL1, and CXCL10 expression in HUVECs, mirroring the same decrease found in Treg cocultures. In the APC(min/+) mouse model of intestinal cancer, nSMase2 is lower in tumor endothelial cells than in unaffected small intestine and chronic treatment with a nSMase2 inhibitor suppressed the increased migration that is otherwise seen in the absence of Tregs. We conclude that nSMase2 is an important mediator in endothelial cells supporting transendothelial migration, which may be targeted by Tregs to reduce T-cell migration into tumors.
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| 19. |
- Akeus, Paulina, et al.
(författare)
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Treg-cell depletion promotes chemokine production and accumulation of CXCR3(+) conventional T cells in intestinal tumors.
- 2015
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Ingår i: European journal of immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 45:6, s. 1654-66
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Tidskriftsartikel (refereegranskat)abstract
- Colorectal cancer (CRC) is one of the most prevalent tumor types worldwide and tumor-infiltrating T cells are crucial for anti-tumor immunity. We previously demonstrated that Treg cells from CRC patients inhibit transendothelial migration of conventional T cells. However, it remains unclear if local Treg cells affect lymphocyte migration into colonic tumors. By breeding APC(Min/+) mice with depletion of regulatory T cells mice, expressing the diphtheria toxin receptor under the control of the FoxP3 promoter, we were able to selectively deplete Treg cells in tumor-bearing mice, and investigate the impact of these cells on the infiltration of conventional T cells into intestinal tumors. Short-term Treg-cell depletion led to a substantial increase in the frequencies of T cells in the tumors, attributed by both increased infiltration and proliferation of T cells in the Treg-cell-depleted tumors. We also demonstrate a selective increase of the chemokines CXCL9 and CXCL10 in Treg-cell-depleted tumors, which were accompanied by accumulation of CXCR3(+) T cells, and increased IFN-γ mRNA expression. In conclusion, Treg-cell depletion increases the accumulation of conventional T cells in intestinal tumors, and targeting Treg cells could be a possible anti-tumor immunotherapy, which not only affects T-cell effector functions, but also their recruitment to tumors.
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| 20. |
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