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  • 1
    Keywords: RECEPTOR ; CELLS ; EXPRESSION ; IN-VITRO ; proliferation ; IN-VIVO ; MODEL ; DISEASE ; DISTINCT ; MICE ; ACTIVATED MACROPHAGES ; ACTIVATION ; COMPLEX ; CRESCENTIC GLOMERULONEPHRITIS ; INJURIES ; LIGAND ; MESANGIAL CELLS ; MONOCYTE ARREST ; NEPHRITIS ; NITRIC-OXIDE ; RANTES ; RESPONSES
    Abstract: The chemokine CC chemokine ligand (CCL)5/RANTES as well as its respective receptor CCR5 mediate leukocyte infiltration during inflammation and are up-regulated early during the course of glomerulonephritis (GN). We tested the effects of the two CCL5/RANTES blocking analogs, Met-RANTES and amino-oxypentane- RANTES, on the course of horse apoferritin (RAF)induced GN. HAF-injected control mice had proliferative GN with mesangial immune complex deposits of IgG and HAF. Daily i.p. injections of Met-RANTES or amino-oxypentane-RANTES markedly reduced glomerular cell proliferation and glomerular macrophage infiltration, which is usually associated with less glomerular injury and proteinuria in RAF-GN. Surprisingly, however, RAF-GN mice treated with both analogs showed worse disease with mesangiolysis, capillary obstruction, and nephrotic range albuminuria. These findings were associated with an enhancing effect of the CCL5/RANTES analogs on the macrophage activation state, characterized by a distinct morphology and increased inducible NO synthetase expression in vitro and in vivo, but a reduced uptake of apoptotic cells in vivo. The Immoral response and the Th1/Th2 balance in HAF-GN and mesangial cell proliferation in vitro were not affected by the CCL5/RANTES analogs. We conclude that, despite blocking local leukocyte recruitment, chemokine analogs can aggravate some specific disease models, most likely due to interactions with systemic immune reactions, including the removal of apoptotic cells and inducible NO synthetase expression
    Type of Publication: Journal article published
    PubMed ID: 12759447
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  • 2
    Keywords: APOPTOSIS ; CELLS ; EXPRESSION ; IN-VITRO ; CELL ; Germany ; human ; IN-VIVO ; MODEL ; PATHWAY ; PATHWAYS ; VITRO ; SYSTEM ; DEATH ; DISTINCT ; TIME ; COMPLEX ; COMPLEXES ; primary ; T cell ; T cells ; T-CELL ; T-CELLS ; culture ; activation-induced cell death ; CELL-DEATH ; UP-REGULATION ; CYCLE PROGRESSION ; DISPLAY ; SIGNALING PATHWAY ; SIGNALING PATHWAYS ; B-CELLS ; immune response ; IMMUNE-RESPONSE ; IL-2 ; INITIATION ; FAS-MEDIATED APOPTOSIS ; DISC ; SIGNALING COMPLEX ; ANTIGEN RECEPTOR ; C-FLIPSHORT ; CD95 ; COMPLEX DISC ; FLICE-INHIBITORY PROTEIN ; INTERLEUKIN-2 RECEPTOR
    Abstract: The CD95 (APO-1/Fas) system plays a critical role in activation-induced cell death (AICD) of T cells. We previously described two distinct CD95 (APO-1/Fas) signaling pathways: 1) type I cells show strong death-inducing signaling complex (DISC) formation and mitochondria-independent apoptosis and 2) DISC formation is reduced in type II cells, leading to mitochondria-dependent apoptosis. To investigate the relevance of these pathways, we set up an in vitro model that mimics the initiation and the down phase of an immune response, respectively. Freshly activated human T cells (initiation) are resistant toward CD95-mediated AICD despite high expression of CD95. We previously reported that these T cells show reduced DISC formation. In this study, we show that freshly activated T cells are CD95-type II cells that show high expression levels of Bcl-x(L) and display a block in the mitochondrial apoptosis pathway. Furthermore, we show that, upon prolonged culture (down phase), human T cells undergo a switch from type II to type I cells that renders T cells sensitive to CD95-mediated AICD. Finally, we demonstrate that this switch is dependent on the presence of IL-2. Our observations reveal for the first time that the existence of coexisting CD95 signaling pathways is of physiological relevance
    Type of Publication: Journal article published
    PubMed ID: 12960316
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  • 3
    Keywords: CELLS ; tumor ; carcinoma ; CELL ; COMBINATION ; Germany ; IN-VIVO ; MODEL ; THERAPY ; VIVO ; MOLECULES ; TISSUE ; TUMORS ; MICE ; ACTIVATION ; DNA ; OLIGODEOXYNUCLEOTIDES ; T cell ; T cells ; T-CELL ; T-CELLS ; TOLERANCE ; treatment ; MOLECULE ; MOUSE ; UP-REGULATION ; EFFICACY ; ADHESION ; CARCINOMAS ; STRATEGIES ; CD8(+) ; IMMUNE-RESPONSE ; vaccination ; MOUSE MODEL ; REJECTION ; DE-NOVO ; ADJUVANT ; EFFECTOR ; CROSS-PRESENTATION ; AGENT ; CELL CARCINOMA ; INFILTRATION ; T-CELL-ACTIVATION ; ANTIGEN-TRANSGENIC MICE ; ESTABLISHED TUMORS ; INDUCE REJECTION
    Abstract: In a transgenic mouse model expressing SV40 T Ag (Tag) as a de novo tumor Ag, immune surveillance fails and islet cell carcinomas grow progressively. To develop an anticancer strategy that would be effective in eradicating solid, autochthonously growing tumors, we evaluated the effectiveness of immunostimulatory oligodeoxynucleotides (ODN) with cytosine-guanine-rich (CpG) motifs (CpG-ODN). In a classical vaccination protocol, Tag was administered with CpG-ODN as adjuvant. The antitumor vaccination, however, was only effective in a prophylactic setting, despite the successful activation of a Tag-specific CTL response in vivo. Histological examination demonstrated that even primed immune cells failed to infiltrate tumors once a malignant environment was established. To ensure that effector cells were not limiting, highly activated tumor Ag-specific T cells were transferred into tumor-bearing mice. However, this treatment also failed to result in tumor infiltration and rejection. Therefore, we further tested the efficacy of CpG-ODN as a proinflammatory agent in combination with the transfer of preactivated Tag-specific CD4(+) and CD8(+) T cells. Indeed, this combination therapy p. roved to be highly effective, because CpG-ODN rendered insulinomas permissive for massive infiltration and destruction. The opening of tumor tissue correlated with uptake of CpG-ODN by tissue-resident macrophages and a strong up-regulation of adhesion molecules such as ICAM and VCAM on blood vessel endothelia. These data demonstrate that systemic application of proinflammatory reagents drastically enhances extravasation of effector cells into tumor tissue, an observation that is of general importance for immunotherapy of solid tumors in a clinical setting
    Type of Publication: Journal article published
    PubMed ID: 15128765
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  • 4
    Keywords: APOPTOSIS ; CELLS ; EXPRESSION ; INHIBITOR ; tumor ; CELL ; Germany ; human ; IN-VIVO ; MODEL ; DEATH ; PROTEIN ; PROTEINS ; ACTIVATION ; COMPLEX ; RESPONSES ; COMPLEXES ; primary ; DENDRITIC CELLS ; T cell ; T cells ; T-CELL ; T-CELLS ; DOWN-REGULATION ; culture ; IMMUNE-RESPONSES ; resistance ; CELL-DEATH ; UP-REGULATION ; immune response ; IMMUNE-RESPONSE ; CASPASE 8 ; FAS-MEDIATED APOPTOSIS ; SIGNALING COMPLEX ; EFFECTOR ; Bcl-2 ; FLICE-INHIBITORY PROTEIN ; CASPASE-8 ACTIVATION ; ACQUIRE
    Abstract: In the early phase of an immune response, T cells are activated and acquire effector functions. Whereas these short term activated T cells are resistant to CD95-mediated apoptosis, activated T cells in prolonged culture are readily sensitive, leading to activation-induced cell death and termination of the immune response. The translation inhibitor, cycloheximide, partially overcomes the apoptosis resistance of short term activated primary human T cells. Using this model we show in this study that sensitization of T cells to apoptosis occurs upstream of mitochondria. Neither death-inducing signaling complex formation nor expression of Bcl-2 proteins is altered in sensitized T cells. Although the caspase-8 inhibitor c-FLIPlong was only slightly down-regulated in sensitized T cells, c-FLIPshort became almost undetectable. This correlated with caspase-8 activation and apoptosis. These data suggest that c-FLIPshort, rather than c-FLIPlong, confers resistance of T cells to CD95-mediated apoptosis in the context of immune responses
    Type of Publication: Journal article published
    PubMed ID: 14764686
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  • 5
    Keywords: CELLS ; EXPRESSION ; GROWTH-FACTOR ; proliferation ; CELL ; CELL-PROLIFERATION ; DISEASE ; GENE ; GENES ; PROTEIN ; MICE ; COMPLEX ; RESPONSES ; COMPLEXES ; AP-1 ; T-CELLS ; C-JUN ; NUCLEAR FACTOR ; REGULATOR ; INITIATION ; CYTOKINE ; BINDING-ACTIVITY ; CHONDROITIN SULFATE-E ; E-PROTEOGLYCAN ; IL-6 PROMOTER
    Abstract: The AP-1 complex is composed of c-Jun and c-Fos and is a key component in the regulation of proinflammatory genes. Mast cells play a significant role in the initiation of many inflammatory responses, such as allergy and allergy-associated diseases. In the present work, we characterized the role of c-Fos in mast cell function by investigating IL-3-dependent cell proliferation, degranulation capability, and cytokine expression in c-Fos-deficient mice. In c-Fos-deficient mast cells, we found that FcepsilonRI-mediated degranulation was significantly inhibited, which correlates with the reduced expression of SWAP-70, VAMP-7, and Synaptotagmin I genes, which are involved directly in the degranulation process. These findings show that c-Fos plays an important role in FcepsilonRI-mediated regulation of mast cell function
    Type of Publication: Journal article published
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  • 6
    Keywords: RECEPTOR ; CELLS ; EXPRESSION ; SURVIVAL ; PROTEIN ; RELEASE ; NF-KAPPA-B ; ACTIVATION ; MECHANISM ; MARKER ; ANTIGEN ; DENDRITIC CELLS ; T-CELLS ; MATURATION ; MOBILITY ; UP-REGULATION ; MARKERS ; LYMPHOCYTES ; SIGNALING PATHWAYS ; Jun ; RAGE ; IMMUNITY ; NEURITE OUTGROWTH ; KAPPA-B ; END ; interaction ; CLASS-II ; dendritic cell ; CHROMATIN PROTEIN HMGB1 ; NECROTIC CELLS
    Abstract: High mobility group box 1 (HMGB1) is an abundant and conserved nuclear protein that is released by necrotic cells and acts in the extracellular environment as a primary proinflammatory signal. In this study we show that human dendritic cells, which are specialized in Ag presentation to T cells, actively release their own HMGB1 into the extracellular milieu upon activation. This secreted HMGB1 is necessary for the up-regulation of CD80, CD83, and CD86 surface markers of human dendritic cells and for IL-12 production. The HMGB1 secreted by dendritic cells is also required for the clonal expansion, survival, and functional polarization of naive T cells. Using neutralizing Abs and receptor for advanced glycation end product-deficient (RAGE(-/-)) cells, we demonstrate that RAGE is required for the effect of HMGB1 on dendritic cells. HMGB1/RAGE interaction results in downstream activation of MAPKs and NF-kappa B. The use of an ancient signal of necrosis, HMGB1, by dendritic cells to sustain their own maturation and for activation of T lymphocytes represents a profitable evolutionary mechanism
    Type of Publication: Journal article published
    PubMed ID: 15944249
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  • 7
    Keywords: RECEPTOR ; CELLS ; ENDOTHELIAL-CELLS ; EXPRESSION ; IN-VITRO ; Germany ; VITRO ; DISEASE ; SITE ; SITES ; PATIENT ; ACTIVATION ; DENDRITIC CELLS ; SKIN ; T-CELLS ; BINDING ; ALPHA ; MATURATION ; AMPLIFICATION ; UP-REGULATION ; PATHOGENESIS ; RECRUITMENT ; CHILDREN ; PREVALENCE ; HEALTHY ; chemokine ; CROSS-LINKING ; INITIATION ; inflammation ; PSORIASIS ; SERUM ; endothelial cells ; interaction ; SDF-1 ; RECRUITS ; dendritic cell ; SERUM-LEVELS ; NORMAL SKIN ; CXCL12 ; CCR10 ; DERMATITIS ; LYMPHOCYTE TRAFFICKING
    Abstract: Atopic dermatitis represents a chronically relapsing skin disease with a steadily increasing prevalence of 10-20% in children. Skin-infiltrating T cells, dendritic cells (DC), and mast cells are thought to play a crucial role in its pathogenesis. We report that the expression of the CC chemokine CCL1 (I-309) is significantly and selectively up-regulated in atopic dermatitis in comparison to psoriasis, cutaneous lupus erythematosus, or normal skin. CCL1 serum levels of atopic dermatitis patients are significantly higher than levels in healthy individuals. DC, mast cells, and dermal endothelial cells are abundant sources of CCL1 during atopic skin inflammation and allergen challenge, and Staphylococcus aureus-derived products induce its production. In vitro, binding and cross-linking of IgE on mast cells resulted in a significant up-regulation of this inflammatory chemokine. Its specific receptor, CCR8, is expressed on a small subset of circulating T cells and is abundantly expressed on interstitial DC, Langerhans cells generated in vitro, and their monocytic precursors. Although DC maintain their CCR8(+) status during maturation, brief activation of circulating T cells recruits CCR8 from intracytoplamic stores to the cell surface. Moreover, the inflammatory and atopy-associated chemokine CCL1 synergizes with the homeostatic chemokine CXCL12 (SDF-1 alpha) resulting in the recruitment of T cell and Langerhans cell-like DC. Taken together, these findings suggest that the axis CCL1-CCR8 links adaptive and innate immune functions that play a role in the initiation and amplification of atopic skin inflammation
    Type of Publication: Journal article published
    PubMed ID: 15814739
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  • 8
    Keywords: RECEPTOR ; CELLS ; EXPRESSION ; tumor ; CELL ; Germany ; PROTEINS ; transcription ; TISSUE ; TUMORS ; MICE ; ACTIVATION ; COMPLEX ; LIGAND ; RESPONSES ; COMPLEXES ; CUTTING EDGE ; IFN-GAMMA ; MACROPHAGES ; TRANSCRIPTION FACTOR ; AP-1 ; TISSUES ; SKIN ; TARGET ; STRESS ; STRESS-RESPONSE ; LIGANDS ; NATURAL-KILLER-CELLS ; NK cells ; CD8(+) ; IMMUNE-RESPONSE ; CELL-SURFACE ; RE ; TUMORIGENESIS ; RHEUMATOID-ARTHRITIS ; LEVEL ; MICE LACKING JUNB ; immunology ; TRANSCRIPTION FACTOR AP-1 ; NKG2D RECEPTOR
    Abstract: The activating receptor NKG2D and its ligands RAE-1 play an important role in the NK, gamma delta(+), and CD8(+) T cell-mediated immune response to tumors. Expression levels of RAE-1 on target cells have to be tightly controlled to allow immune cell activation against tumors but to avoid destruction of healthy tissues. In this study, we report that cell surface expression of RAE-1 epsilon is greatly enhanced on cells lacking JunB, a subunit of the transcription complex AP-1. Furthermore, tissue-specific junB knockout mice respond to 12-O-tetradecanoyl-phorbol-13-acetate, a potent AP-1 activator, with markedly increased and sustained epidermal RAE-1 epsilon expression. Accordingly, junB-deficient cells are efficiently killed via NKG2D by NK cells and induce IFN-gamma production. Our data indicate that the transcription factor AP-1, which is involved in tumorigenesis and cellular stress responses, regulates RAE-1 epsilon. Thus, up-regulated RAE-1 epsilon expression due to low levels of JunB could alert immune cells to tumors and stressed cells
    Type of Publication: Journal article published
    PubMed ID: 16365389
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  • 9
    Keywords: CELLS ; EXPRESSION ; BLOOD ; CELL ; Germany ; GENERATION ; POPULATION ; PATIENT ; MECHANISM ; MARKER ; DONOR ; mechanisms ; T cell ; T cells ; T-CELL ; T-CELLS ; SUPPRESSION ; DIFFERENCE ; resistance ; NUMBER ; AGE ; SURFACE ; BETA ; PHENOTYPE ; INDIVIDUALS ; TCR ; DE-NOVO ; PREVALENCE ; PERIPHERAL-BLOOD ; DECLINE ; MULTIPLE-SCLEROSIS ; GUIDELINES ; SUBPOPULATION ; DEFICIENCY ; SUBSET ; CAPACITY ; multiple sclerosis ; USA ; function ; correlation ; DEFECT ; immunology ; DEPLETION ; regulatory T cells ; HOMEOSTASIS ; EXPANSION ; DIAGNOSTIC-CRITERIA ; DYSFUNCTION ; GLATIRAMER ACETATE
    Abstract: The suppressive function of regulatory T cells (T-reg) is impaired in multiple sclerosis (MS) patients. The mechanism underlying the Treg functional defect is unknown. T-reg mature in the thymus and the majority of cells circulating in the periphery rapidly adopt a memory phenotype. Because our own previous findings suggest that the thymic output of T cells is impaired in MS, we hypothesized that an altered T-reg generation may contribute to the suppressive deficiency. We therefore determined the role of T-reg that enter the circulation as recent thymic emigrants (RTE) and, unlike their CD45RO(+) memory counterparts, express CD31 as typical surface marker. We show that the numbers of CD31(+)-coexpressing CD4(+)CD25(+)CD45RA(+)CD45RO-FOXP3(+) T-reg (RTE-T-g) within peripheral blood decline with age and are significantly reduced in MS patients. The reduced de novo generation of RTE-T-reg is compensated by higher proportions of memory T-reg, resulting in a stable cell count of the total T-reg population. Depletion of CD31(+) cells from T-reg diminishes the suppressive capacity of donor but not patient T-reg and neutralizes the difference in inhibitory potencies between the two groups. Overall, there was a clear correlation between T-reg-mediated suppression and the prevalence of RTE-T-reg, indicating that CD31-expressing naive T-reg contribute to the functional properties of the entire T-reg population. Furthermore, patient-derived T-reg, but not healthy T-reg, exhibit a contracted TCR V beta repertoire. These observations ggest that a shift in the homeostatic composition of T-reg subsets related to a reduced thymic-dependent de novo generation of RTE-T-reg with a compensatory expansion of memory Tmg may contribute to the Treg defect associated with MS
    Type of Publication: Journal article published
    PubMed ID: 17617625
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  • 10
    Keywords: RECEPTOR ; APOPTOSIS ; CANCER ; EXPRESSION ; CELL ; human ; IN-VIVO ; PATHWAY ; PATHWAYS ; VIVO ; transcription ; EFFICIENCY ; cell line ; LINES ; TIME ; RESPONSES ; DNA ; INFECTION ; MECHANISM ; KERATINOCYTES ; cell cycle ; CELL-CYCLE ; CELL-LINES ; CYCLE ; E7 ; papillomavirus ; SEQUENCE ; virus ; PROMOTER ; cervical cancer ; CERVICAL-CANCER ; CELL-LINE ; LINE ; human papillomavirus ; HPV ; E6 ; HUMAN KERATINOCYTES ; HUMAN-PAPILLOMAVIRUS ; ONCOPROTEIN ; IMMUNE-RESPONSE ; DOUBLE-STRANDED-RNA ; DIFFERENTIAL EXPRESSION ; cell lines ; TOLL-LIKE RECEPTORS ; RECOMBINANT ; RE ; keratinocyte ; VIRUS-INFECTION ; development ; EVENTS ; function ; LOSSES ; PLASMACYTOID DENDRITIC CELLS ; CANCERS ; in vivo ; immunology ; INHIBIT ; carcinogenic ; IMMUNE ACTIVATION ; IMMUNOLOGICAL RESPONSES ; TRANSFORMING PROPERTIES ; TYPE-18 ; VACCINIA-VIRUS
    Abstract: Cervical cancer development is linked to the persistent infection by high-risk mucosal human papillomaviruses (HPVs) types. The E6 and E7 major oncoproteins from this dsDNA virus play a key role in the deregulation of the cell cycle, apoptosis, and adaptive immune surveillance. In this study, we show for the first time that HPV type 16 (HPV16), the most carcinogenic type among the high-risk subgroup, interferes with innate immunity by affecting the expression of TLRs. Infection of human primary keratinocytes with HPV16 E6 and E7 recombinant retroviruses inhibits TLR9 transcription and hence functional loss of TLR9-regulated pathways. Similar findings were achieved in HPV16-positive cancer-derived cell lines and primary cervical cancers, demonstrating that this event occurs also in an in vivo context. Interestingly, E6 and E7 from the low-risk HPV type 6 are unable to down-regulate the TLR9 promoter. In addition, E6 and E7 from the high-risk HPV type 18, which are known to persist less competently in the host than HPV16, have reduced efficiency compared with HPV16 in inhibiting TLR9 transcription. Furthermore, a CpG motif derived from the HPV16 E6 DNA sequence activated TLR9, indicating this virus is able to initiate innate responses via the receptor it later down-regulates. This study reveals a novel mechanism used by HPV16 to suppress the host immune response by deregulating the TLR9 transcript, providing evidence that abolishing innate responses may be a crucial step involved in the carcinogenic events mediated by HPVs
    Type of Publication: Journal article published
    PubMed ID: 17312167
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