| 1. |
- Sarhan, Dhifaf, et al.
(författare)
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Activated monocytes augment TRAIL-mediated cytotoxicity by human NK cells through release of IFN-gamma
- 2013
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Ingår i: European Journal of Immunology. - Stockholm : Karolinska Institutet, Dept of Oncology-Pathology. - 1521-4141 .- 0014-2980.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Natural killer (NK) cells are innate lymphocytes that are able to directly kill tumor cells through different mechanisms including ligation of TNF-related apoptosis-inducing ligand (TRAIL) receptors. Zoledronic acid (ZA) is a bisphosphonate known to upregulate the expression of TRAIL on human γδ T cells. Here, we investigated whether exposure to ZA would upregulate TRAIL expression on human NK cells and augment their cytotoxicity against tumor cells. When cocultured with monocytes, treatment with ZA and IL-2 resulted in a significant upregulation of TRAIL expression on human NK cells (p = 0.002). Consequently, ZA-primed NK cells were significantly more cytotoxic against TRAIL sensitive tumor cells (p < 0.0001). In the presence of ZA and IL-2, monocytes produced high levels of IFN-γ; when cultured in the presence of neutralizing antibodies to IFN-γ, TRAIL expression and TRAIL-mediated cytotoxicity of NK cells were significantly reduced. Furthermore, in tumor-bearing SCID/Beige mice, a significant delayed tumor progression and prolonged survival was observed after infusion of ZA-primed NK cells compared with that observed in mice infused with unprimed NK cells. These findings represent a novel approach to potentiate TRAIL-mediated apoptosis by adoptively infused NK cells that could improve the outcome in patients with cancer.
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| 2. |
- 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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| 3. |
- Allerbring, E. B., et al.
(författare)
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Unexpected T-cell recognition of an altered peptide ligand is driven by reversed thermodynamics
- 2012
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 42:11, s. 2990-3000
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Tidskriftsartikel (refereegranskat)abstract
- The molecular basis underlying T-cell recognition of MHC molecules presenting altered peptide ligands is still not wellestablished. A hierarchy of T-cell activation by MHC class I-restricted altered peptide ligands has been defined using the T-cell receptor P14 specific for H-2Db in complex with the immunodominant lymphocytic choriomeningitis virus peptide gp33 (KAVYNFATM). While substitution of tyrosine to phenylalanine (Y4F) or serine (Y4S) abolished recognition by P14, the TCR unexpectedly recognized H-2Db in complex with the alanine-substituted semiagonist Y4A, which displayed the most significant structural modification. The observed functional hierarchy gp33 > Y4A > Y4S = Y4F was neither due to higher stabilization capacity nor to differences in structural conformation. However, thermodynamic analysis demonstrated that while recognition of the full agonist H-2Db/gp33 was strictly enthalpy driven, recognition of the weak agonist H-2Db/Y4A was instead entropy driven with a large reduction in the favorable enthalpy term. The fourfold larger negative heat capacity derived for the interaction of P14 with H-2Db/gp33 compared with H-2Db/Y4A can possibly be explained by higher water entrapment at the TCR/MHC interface, which is also consistent with the measured opposite entropy contributions for the interactions of P14 with both MHCs. In conclusion, this study demonstrates that P14 makes use of different strategies to adapt to structural modifications in the MHC/peptide complex.
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| 8. |
- Biswas, Amlan, et al.
(författare)
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Negative regulation of Toll-like receptor signaling plays an essential role in homeostasis of the intestine.
- 2011
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Ingår i: European journal of immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 41:1, s. 182-94
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Tidskriftsartikel (refereegranskat)abstract
- A healthy intestinal tract is characterized by controlled homeostasis due to the balanced interaction between commensal bacteria and the host mucosal immune system. Human and animal model studies have supported the hypothesis that breakdown of this homeostasis may underlie the pathogenesis of inflammatory bowel diseases. However, it is not well understood how intestinal microflora stimulate the intestinal mucosal immune system and how such activation is regulated. Using a spontaneous, commensal bacteria-dependent colitis model in IL-10-deficient mice, we investigated the role of TLR and their negative regulation in intestinal homeostasis. In addition to IL-10(-/-) MyD88(-/-) mice, IL-10(-/-) TLR4(-/-) mice exhibited reduced colitis compared to IL-10(-/-) mice, indicating that TLR4 signaling plays an important role in inducing colitis. Interestingly, the expression of IRAK-M, a negative regulator of TLR signaling, is dependent on intestinal commensal flora, as IRAK-M expression was reduced in mice re-derived into a germ-free environment, and introduction of commensal bacteria into germ-free mice induced IRAK-M expression. IL-10(-/-) IRAK-M(-/-) mice exhibited exacerbated colitis with increased inflammatory cytokine gene expression. Therefore, this study indicates that intestinal microflora stimulate the colitogenic immune system through TLR and negative regulation of TLR signaling is essential in maintaining intestinal homeostasis.
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| 9. |
- Bros, Matthias, et al.
(författare)
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Mutated cylindromatosis gene affects the functional state of dendritic cells
- 2010
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Ingår i: European Journal of Immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 40:10, s. 2848-2857
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Tidskriftsartikel (refereegranskat)abstract
- Cylindromatosis gene (CYLD) is a ubiquitously expressed deubiquitinating enzyme, which interacts with members of the NF-kappa B signaling pathway and attenuates NF-kappa B and JNK signaling. Here, we report that DC derived from transgenic mice, which solely express a naturally occurring CYLD isoform (CYLDex7/8), display a higher content of nuclear RelB and express elevated levels of NF-kappa B family members as well as of known NF-kappa B-target genes comprising costimulatory molecules and pro-inflammatory cytokines, as compared with WT DC. Accordingly, unstimulated CYLDex7/8 DC exhibited a significantly higher primary allogenic T-cell stimulatory capacity than WT DC and exerted no tolerogenic activity. Transduction of unstimulated CYLDex7/8 DC with relB-specific shRNA reduced their T-cell stimulatory capacity. Treatment with the synthetic glucocorticoid dexamethasone known to inhibit NF-kappa B and AP-1 activity reverted the pro-immunogenic phenotype and function of CYLDex7/8 DC and re-established their tolerogenic function. DC derived from CYLD knockout mice showed no functional alterations compared with WT DC. Therefore, although complete loss of CYLD may be compensated for by other endogenous NF-kappa B inhibitors, CYLDex7/8 acts in a dominant negative manner. Our findings raise the question of whether genetic defects associated with increased NF-kappa B activity may result in disturbed maintenance of peripheral tolerance.
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| 10. |
- Che, Karlhans F, et al.
(författare)
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HIV-1 impairs in vitro priming of naïve T cells and gives rise to contact-dependent suppressor T cells
- 2010
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 40:8, s. 2248-2258
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Tidskriftsartikel (refereegranskat)abstract
- Priming of T cells in lymphoid tissues of HIV-infected individuals occurs in the presence of HIV-1. DC in this milieu activate T cells and disseminate HIV-1 to newly activated T cells, the outcome of which may have serious implications in the development of optimal antiviral responses. We investigated the effects of HIV-1 on DC-naïve T-cell interactions using an allogeneic in vitro system. Our data demonstrate a dramatic decrease in the primary expansion of naïve T cells when cultured with HIV-1-exposed DC. CD4(+) and CD8(+) T cells showed enhanced expression of PD-1 and TRAIL, whereas CTLA-4 expression was observed on CD4(+) T cells. It is worth noting that T cells primed in the presence of HIV-1 suppressed priming of other naïve T cells in a contact-dependent manner. We identified PD-1, CTLA-4, and TRAIL pathways as responsible for this suppresion, as blocking these negative molecules restored T-cell proliferation to a higher degree. In conclusion, the presence of HIV-1 during DC priming produced cells with inhibitory effects on T-cell activation and proliferation, i.e. suppressor T cells, a mechanism that could contribute to the enhancement of HIV-1 pathogenesis.
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