| 1. |
- Arencibia, I, et al.
(författare)
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Yersinia invasin, a bacterial beta1-integrin ligand, is a potent inducer of lymphocyte motility and migration to collagen type IV and fibronectin.
- 1997
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Ingår i: Journal of Immunology. - 0022-1767 .- 1550-6606. ; 159:4, s. 1853-9
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Tidskriftsartikel (refereegranskat)abstract
- The Yersinia pseudotuberculosis invasin protein was found to be a potent inducer of pseudopodia formation and chemotactic and haptotactic migration in human T lymphocytes. Checkerboard analysis confirmed that migration was directional. The Yersinia invasin triggered migration of otherwise poorly migratory normal T cells on fibronectin and in particular on collagen type IV, and augmented the migration of leukemic T cell lines on these components. Invasin-induced lymphocyte migration was inhibited by staurosporin that selectively prevented pseudopodia formation but, noteworthy, augmented adhesion. The motogenic and attractant properties of invasin (Inv) were mediated via beta1-integrins, as shown by lack of effect of Inv on the motility of a beta1-integrin-negative lymphoid cell line and inhibition of invasin-induced lymphocyte motility by anti-beta1 Abs. Inv was markedly more effective than the extracellular matrix components fibronectin, collagen type IV, and laminin, which also interact with lymphocyte beta1-integrins, with respect to induction of pseudopodia, chemotaxis, and haptotaxis. Thus, Yersinia invasin is a model ligand for induction of lymphocyte motility via beta1-integrins. The extraordinary capacity of Inv to trigger and guide T lymphocyte motility and potentiate lymphocyte migration to extracellular matrix components may be of pathogenetic significance for the movement of lymphocytes to extraintestinal sites secondary to Yersinia infection.
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| 2. |
- Ekdahl, K N, et al.
(författare)
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Phosphorylation of complement component C3 and C3 fragments by a human platelet protein kinase. Inhibition of factor I-mediated cleavage of C3b.
- 1995
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Ingår i: Journal of Immunology. - 0022-1767 .- 1550-6606. ; 154:12, s. 6502-6510
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Tidskriftsartikel (refereegranskat)abstract
- Phosphorylation of C3 in vitro has been shown previously to lead to significantly altered function of the protein. Platelets are known to contain and release considerable amounts of protein kinases and ATP, which are prerequisites for protein phosphorylation. The aim of the present study was to investigate whether C3 is phosphorylated extracellularly by human platelets. Platelet-rich plasma was stimulated by human aggregated gamma-globulin or ADP. The remaining cells were removed by centrifugation, and the plasma was incubated with [gamma-32P]ATP. After precipitation with Sepharose-bound Abs to C3c followed by SDS-PAGE, it was shown that C3 was phosphorylated in the alpha-chain by a protein kinase dependent on Mn2+, Ca2+, or Mg2+ ions. The supernatant from washed, activated platelets was incubated with purified C3 or soluble or activated thiol Sepharose-bound C3b, together with [gamma-32P]ATP. Phosphorylation was seen in the alpha-chain of C3, and to the same extent in the alpha'-chain of both C3b preparations. The analysis of acid hydrolysate demonstrated that C3 contained 32P-labeled Thr and 32P-labeled Ser. After extensive proteolysis with trypsin, the major phosphorylation site was located to a peptide of 3 to 4 kDa that was bound to the activated thiol Sepharose via the free sulphydryl group in the C3d fragment. Incubation of phosphorylated C3b with factors I and H showed that phosphorylation inhibited the cleavage of the alpha'-chain of C3b. The results in this study suggest that phosphorylation is a regulator of C3 during platelet activation induced, for example, by immune complexes.
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| 3. |
- Kleinau, Sandra, et al.
(författare)
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Importance of CD23 for collagen-induced arthritis : delayed onset and reduced severity in CD23-deficient mice
- 1999
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Ingår i: Journal of Immunology. - 0022-1767 .- 1550-6606. ; 162:7, s. 4266-4270
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Tidskriftsartikel (refereegranskat)abstract
- Increased expression of the low affinity receptor for IgE, FcepsilonRII/CD23 has been observed in rheumatoid arthritis. In view of this, we have investigated the expression and influence of CD23 in collagen-induced arthritis (CIA), an animal model for rheumatoid arthritis. CD23+ cells were analyzed in lymph nodes of DBA/1 mice immunized with bovine collagen type II (BCII) in CFA or with CFA only. The percentage of CD23+ lymph node cells was increased in both BCII/CFA- and CFA-immunized mice at 1, 3, and 7 wk after immunization compared with unimmunized mice, indicating a role for the adjuvant to trigger general inflammation and CD23 expression. To investigate the functional role of CD23 in CIA, CD23-deficient mice on the DBA/1 genetic background were studied. After immunization with BCII/CFA, these mice developed CIA with delayed onset and reduced severity compared with wild-type mice. These findings suggest that an increased number of CD23+ cells is part of an inflammatory response and that CD23 expression is of pathogenic importance in the arthritic process.
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| 4. |
- Kohrgruber, N, et al.
(författare)
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Survival, maturation, and function of CD11c- and CD11c+ peripheral blood dendritic cells are differentially regulated by cytokines
- 1999
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Ingår i: Journal of Immunology. - : American association of immunologists. - 0022-1767 .- 1550-6606. ; 163:6, s. 3250-3259
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Tidskriftsartikel (refereegranskat)abstract
- Two types of dendritic cells (DC) are circulating in human blood and can be identified by their differential expression of the myeloid Ag CD11c. In this study, we show that CD11c- peripheral blood (PB)-DC correspond to plasmacytoid DC of lymphoid tissue not only by their surface Ag expression profile but, more impressively, by their peculiar ultramorphology. We also demonstrate that CD11c- and CD11c+ DC differ in the quality of their response to and in their requirement for certain cytokines. Freshly isolated CD11c- cells depend on IL-3 for survival and use autocrine or exogenous TNF-alpha as maturation signal, leading to the appearance of a highly dendritic phenotype, the up-regulation and redistribution of MHC class II from lysosomal compartments to the plasma membrane, the increased expression of costimulatory molecules, and the switch from a high Ag-processing to a low Ag-processing/potent accessory cell mode. Surprisingly, IL-4 efficiently killed freshly isolated CD11c- PB-DC, but did not impair the viability of CD11c+ PB-DC and, together with GM-CSF, induced maturation of these cells. A direct functional comparison revealed that neo-Ag-modified and subsequently matured CD11c- but to a lesser extent CD11c+ DC were able to prime naive Ag-specific CD4+ T cells. Our findings show that two diverse DC types respond to certain T cell-derived cytokines in a differential manner and, thus, suggest that suppression or activation of functionally diverse DC types may be a novel mechanism for the regulation of the quantity and quality of immune responses.
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| 5. |
- Lejon, Kristina, 1967-, et al.
(författare)
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Isolation of self antigen-reactive cells from inflamed islets of nonobese diabetic mice using CD4high expression as a marker
- 1999
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 163:10, s. 5708-5714
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Tidskriftsartikel (refereegranskat)abstract
- The low precursor frequency of Ag-reactive CD4+ T cells has been a barrier to the study of CD4+ T cell responses to conventional Ags as well as CD4+ T cell responses to autoantigens recognized during the course of an autoimmune disease. We have recently reported that all "conventional Ag" reactive CD4+ T cells are contained within the subpopulation expressing high levels of the CD4 molecule, termed CD4high. We have identified a CD4high population in the islets of Langerhans of prediabetic nonobese diabetic (NOD) mice that is extremely potent in transferring disease. As few as 500 CD4high islet-infiltrating CD4+ T cells transferred insulin-dependent diabetes mellitus to CD8 reconstituted NOD-SCID mice within 30 days of transfer. In contrast, CD4high T cells isolated from either NOD spleen or salivary glands did not transfer insulin-dependent diabetes mellitus into similar CD8-reconstituted NOD-SCID recipients. These data indicate that the precursor frequency of NOD islet-reactive, pathogenic CD4+ T cells is much higher in the prediabetic NOD pancreas than in these other organs. The islet-infiltrating CD4high T cells displayed selected memory markers, by cell surface analysis, and displayed a Th 1 phenotype by RNase protection assay, but had a marked decrease in IL-4 mRNA determined by quantitative real time PCR when compared with the less pathogenic CD4normal islet-infiltrating T cells. Use of the CD4high marker to select Ag activated T cells represents a tool to isolate and study pathogenic CD4+ T cells from autoimmune lesions in which the Ag has not been previously defined.
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| 6. |
- Liberg, David, et al.
(författare)
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Differentiation-specific, octamer-dependent costimulation of κ transcription
- 1998
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 160:8, s. 3899-3907
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Tidskriftsartikel (refereegranskat)abstract
- By mutational analysis of the octamer-TATA box intervening region in the mouse SP6 κ promoter, we have mapped two octamer-dependent, costimulatory regions, A and B. The A region was active in late B cells only, while the B region was active throughout B cell differentiation. The B region was TATA proximal and contained a heptamer and an E box of the E2A type that is common in Vκ promoters. Mutation of the heptamer element did not decrease transcriptional stimulation from this region, but mutations in, or immediately 5' of, the E box core sequence did. A protein binding to this region could be detected in nuclear extracts. The complex could only partially be competed with a μE5 binding site and could not be supershifted with Abs raised to E2A gene products, indicating that it may represent a novel E-box binding complex. The A region was located proximal to the octamer and contained a CCCT element that is conserved both with regard to position and sequence in human VκII promoters. By mutational analysis, the transcriptional stimulatory activity was mapped to the CCCT element that also is part of an early B cell factor (EBF) binding site. In late B cells, a novel protein (FA), which did not bind to the EBF binding site in the mb1 promoter, interacted with the A region. This protein was found to be expressed at lower levels in early B cells as well as in HeLa cells. Thus, the octamer-flanking sequence contains positive control elements that may act independently but that differ in the stage of B cell differentiation at which they are active. One of these factors is an example of an ubiquitously expressed transcription factor that participate in differentiation-specific transcriptional activation.
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| 7. |
- Lobell, Anna, et al.
(författare)
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Presence of CpG DNA and the local cytokine milieu determine the efficacy of suppressive DNA vaccination in experimental autoimmune encephalomyelitis
- 1999
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Ingår i: Journal of Immunology. - 0022-1767 .- 1550-6606. ; 163:9, s. 4754-4762
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Tidskriftsartikel (refereegranskat)abstract
- We here study the adjuvant properties of immunostimulatory DNA sequences (ISS) and coinjected cytokine-coding cDNA in suppressive vaccination with DNA encoding an autoantigenic peptide, myelin basic protein peptide 68-85, against Lewis rat experimental autoimmune encephalomyelitis (EAE). EAE is an autoaggressive, T1-mediated disease of the CNS. ISS are unmethylated CpG motifs found in bacterial DNA, which can induce production of type 1 cytokines in vertebrates through the innate immune system. Because ISS in the plasmid backbone are necessary for efficient DNA vaccination, we studied the effect of one such ISS, the 5'-AACGTT-3' motif, in our system. Treatment with a DNA vaccine encoding myelin basic protein peptide 68-85 and containing three ISS of 5'-AACGTT-3' sequence suppressed clinical signs of EAE, while a corresponding DNA vaccine without such ISS had no effect. We further observed reduced proliferative T cell responses in rats treated with the ISS-containing DNA vaccine, compared with controls. We also studied the possible impact of coinjection of plasmid DNA encoding rat cytokines IL-4, IL-10, GM-CSF, and TNF-alpha with the ISS-containing DNA vaccine. Coinjection of IL-4-, IL-10-, or TNF-alpha-coding cDNA inhibited the suppressive effect of the DNA vaccine on EAE, whereas GM-CSF-coding cDNA had no effect. Coinjection of cytokine-coding cDNA with the ISS-deficient DNA vaccine failed to alter clinical signs of EAE. We conclude that the presence of ISS and induction of a local T1 cytokine milieu is decisive for specific protective DNA vaccination in EAE.
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| 8. |
- Los, Marek Jan, et al.
(författare)
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Human T cell leukemia virus-I (HTLV-I) Tax-mediated apoptosis in activated T cells requires an enhanced intracellular prooxidant state
- 1998
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Ingår i: Journal of Immunology. - : American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 161:6, s. 3050-3055
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Tidskriftsartikel (refereegranskat)abstract
- We have shown that an estradiol-dependent activation of human T cell leukemia virus-I Tax leads to the inhibition of cell proliferation and to the induction of apoptosis, The present study demonstrates that a hormone-dependent activation of Tax promotes an enhanced prooxidant state in stably transfected Jurkat cells as measured by changes in the intracellular levels of glutathione and H2O2; these changes are followed by apoptotic cell death. Additional stimulation of the CD3/TCR pathway enhances the oxidative and apoptotic effects. Both Tax-mediated apoptosis and oxidative stress can be potently suppressed by antioxidants, as is seen with the administration of recombinant thioredoxin (adult T cell leukemia derived factor) or pyrrolidine dithiocarbamate. Hormone-induced Tax activation induces a long-lasting activation of NF-kappa B, which is a major target of reactive oxygen ntermediates. The long-term exposure of Jurkat cells to hormone eventually results in a selection of cell clones that have lost Tax activity. A subsequent transfection of these apparently "nonresponsive" clones allows the recovery of Tax responses in these cells. Our observations indicate that changes in the intracellular redox status mag be a determining factor in Tax-mediated DNA damage, apoptosis, and selection against the long-term expression of Tax function.
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| 9. |
- Lundqvist, C, et al.
(författare)
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Intraepithelial lymphocytes in human gut have lytic potential and a cytokine profile that suggest T helper 1 and cytotoxic functions.
- 1996
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Ingår i: Journal of Immunology. - 0022-1767 .- 1550-6606. ; 157:5, s. 1926-34
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Tidskriftsartikel (refereegranskat)abstract
- The functional properties of intraepithelial lymphocytes (IEL) in normal human jejunum, ileum, and colon were investigated. Cytokine mRNA expression in IEL and enterocytes was determined by reverse transcriptase-PCR and IFN-gamma+ IEL by immunohistochemistry. Polyclonal activators were used to study proliferation and IFN-gamma secretion of IEL, and an anti-CD3-mediated redirected cytotoxicity assay was used to determine the lytic potential of IEL. Freshly isolated IEL at all three gut levels expressed mRNA for IL-1 beta, IL-2, IL-8, IFN-gamma, and TNF-alpha. Approximately 10% of IEL produced IFN-gamma, suggesting that IEL are immunologically active in vivo, performing similar functions along the intestine. IEL could be stimulated further in vitro to express IL-10, TNF-beta, and TGF-beta 1, while no Th2-type cytokines were induced, suggesting suppressive and cytolytic functions for IEL. All three jejunal IEL subpopulations (CD4-CD8-TCR-gamma delta+, CD4+TCR-alpha beta+, CD8+TCR-alpha beta+) expressed the same four cytokines, IL-2, IL-8, IFN-gamma, and TNF-alpha, indicating that CD4+TCR-alpha beta+ IEL are Th1 cells and that TCR-gamma delta+ IEL and CD8+TCR-alpha beta+ IEL include cytotoxic effector cells. Indeed, freshly isolated jejunal IEL displayed cytolytic activity. IEL were induced to proliferation by anti-CD3/TCR complex mAbs and leukoagglutinin, but not by Con A. There was no correlation between the magnitude of the proliferative response and the amounts of secreted IFN-gamma. Enterocytes expressed IL-1 beta and IL-8, and sometimes TNF-alpha. Although jejunal enterocytes express HLA-DR and hsp60, Ag presentation by these cells may induce anergy since their cytokine profile is different from that of classical APCs.
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| 10. |
- Maurer, D, et al.
(författare)
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Peripheral blood dendritic cells express Fc epsilon RI as a complex composed of Fc epsilon RI alpha- and Fc epsilon RI gamma-chains and can use this receptor for IgE-mediated allergen presentation
- 1996
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Ingår i: Journal of Immunology. - : American association of immunologists. - 0022-1767 .- 1550-6606. ; 157:2, s. 607-616
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Tidskriftsartikel (refereegranskat)abstract
- Originally limited to basophils and mast cells, the spectrum of high affinity IgE receptor (Fc epsilon RI-bearing cells has expanded recently to include Langerhans cells, dermal dendritic cells (DC), monocytes, and eosinophils. As a result of studies on the distribution, structure, and function of Fc epsilon RI on APCs, we discovered a minor nonbasophil, nonmonocyte PBMC population that can bind IgE via Fc epsilon RI. This receptor occurs on the surface of these cells as a multimeric structure containing Fc epsilon RI alpha- and Fc epsilon RI gamma-chains but, unlike its counterpart on basophils, lacking Fc epsilon RI beta. Further experiments revealed that these Fc epsilon RI alpha gamma-expressing cells closely resemble peripheral blood DC by immunophenotype (HLA-DRhigh, HLA-DQhhigh; CD4+, CD11a+, CD32+, CD33+, B7/2 (CD86)+; CD11blow, CD14low, CD40low, CD54low, CD64low) and cell morphology. These features allowed us to isolate Fc epsilon RI-expressing DC from the peripheral blood and to investigate their immunostimulatory properties. We found Fc epsilon RI-positive DC to be efficient stimulators of both primary (allogeneic MLR) and Fc epsilon RI/IgE-dependent, secondary T cell responses at low cell numbers. Thus, Fc epsilon RI-expressing DC may not only amplify established type I allergic immune reactions but, unlike Fc epsilon RI-positive semiprofessional APCs, may be able to prime naive T cells to common and/or cryptic epitopes of IgE-reactive Ags.
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