| 1. |
- Bjersing, Jan, 1966, et al.
(författare)
-
Anti-proliferative effects of phosphodiester oligodeoxynucleotides
- 2004
-
Ingår i: Immunobiology. - : Elsevier BV. - 0171-2985. ; 209:8, s. 637-45
-
Tidskriftsartikel (refereegranskat)abstract
- The immunostimulatory effects of cytosine-phosphate-guanosine (CpG)-containing oligodeoxynucleotides (ODNs) have been extensively documented. In this paper, we describe the inhibitory effects of ODNs that contain natural phosphodiester backbones (O-ODNs) on the immunostimulation caused by CpG-containing phosphorothioated ODNs (CpG-S). CpG-S stimulation of mouse splenocyte proliferation was reduced by the addition of O-ODNs that contained or lacked the CpG-motif (CpG-containing phosphodiester oligodeoxynucleotide, CpG-O or GpC-O). The total number of cultured splenocytes was up-regulated by CpG-S, whereas repetitive addition of O-ODNs to the cell cultures inhibited this effect. The frequency of T2-like B cells was found to be increased by CpG-S. The culture supernatants of CpG-S-treated splenocytes contained elevated levels of IL-10 and IL-6. However, IL-10 and IL-6 production was down-regulated significantly by the combination of CpG-S and either CpG-O or GpC-O. The O-ODN mediated inhibition of proliferation was less pronounced in IL-10-/- mice. Thus, the O-ODNs, irrespective of CpG content, exerted inhibitory activities on the proliferation of B cells. These anti-proliferative effects appear to be mediated both by the down-regulation of IL-10 production and increased apoptosis.
|
|
| 2. |
- Bjersing, Jan, 1966, et al.
(författare)
-
Impact of site-specific nucleobase deletions on the arthritogenicity of DNA
- 2004
-
Ingår i: Inflammation. - 0360-3997. ; 28:3, s. 159-68
-
Tidskriftsartikel (refereegranskat)abstract
- Oligodeoxynucleotides (ODN) containing unmethylated CpG motifs (CpG ODN) potently stimulate the innate and acquired immune system. We have compared the in vivo and in vitro inflammatogenic properties of CpG ODNs containing a specific nucleobase deletion either 5'-upstream (ODN-2) or 3'-downstream (ODN-3) of the CpG motif, comparing with a prototype CpG ODN (ODN-1). The frequency of arthritis was similar after intra-articular (i.a.) injections of ODN-1 or ODN-3, but was significantly lower (p < 0.02) after i.a. injections of ODN-2. In vitro production of the pro-inflammatory cytokine TNF-alpha was higher in mouse spleen cell cultures exposed to ODN-2 in comparison to ODN-1. In addition, the level of IL-10 induced by ODN-2 was higher than that induced by ODN-1. On the other hand, TNF-alpha, IL-10, and MCP-1 levels, as well as splenocyte proliferative responses were all significantly lower for ODN-3 than for ODN-1. These results suggest that a 5'-upstream nucleobase deletion reduces arthritogenicity, while maintaining or increasing the production of pro- and anti-inflammatory factors. In contrast, a 3'-downstream nucleobase deletion has no effect on arthritogenicity, despite significantly lower levels of proliferation and pro- and anti-inflammatory cytokines, compared with ODN-1. This study indicates that specific structural elements within the ODN sequence but outside the CpG motif, modulate the immunostimulatory properties of CpG ODNs.
|
|
| 3. |
- Bjersing, Jan, 1966, et al.
(författare)
-
The arthritogenic and immunostimulatory properties of phosphorothioate oligodeoxynucleotides rely on synergy between the activities of the nuclease-resistant backbone and CpG motifs
- 2004
-
Ingår i: Inflammation. - 0360-3997. ; 28:1, s. 39-51
-
Tidskriftsartikel (refereegranskat)abstract
- Experiments with immunostimulatory unmethylated CpG-containing DNA are usually conducted with nuclease-protected phosphorothioate oligodeoxynucleotides (S-ODNs), rather than phosphodiester oligodeoxynucleotides (O-ODNs). We compared the murine immune responses to S-ODNs and O-ODNs that either contained or lacked CpG motifs. Both CpG and non-CpG S-ODNs induced synovitis, as did sequence-matched CpG O-ODN, but not GpC O-ODN. There was a minimum length requirement for arthritogenic S-ODNs since a CpC dinucleotide S-ODN did not induce arthritis. There were both sequence- (CpG > non-CpG) and backbone-dependent (S-ODN > O-ODN) differences in the levels of DNA-induced arthritis upon intra-articular injection with the ODNs. However, CpG O-ODN being an exception, induced more severe arthritis than the GpC S-ODN. The levels of in vitro proliferation and production of IL-6, TNF-alpha, IL-12, and RANTES by splenocytes following exposure to CpG S-ODN were significantly higher than those induced by CpG O-ODN. In addition, both proliferative responses and cytokine production induced by S-ODN-stimulated splenocytes increased significantly when the S-ODN contained a CpG motif. Transcription factor NFkappaB was activated by both CpG S-ODN and CpG O-ODN but interestingly not by GpC S-ODN. This indicates that the NFkappaB signal pathway modulates CpG-mediated immunostimulation, while sequence-independent immune activation by the phosphorothioate backbone is probably signalled via a different pathway.
|
|
| 4. |
- Bokarewa, Maria, 1963, et al.
(författare)
-
Human alpha -defensins neutralize fibrinolytic activity exerted by staphylokinase
- 2004
-
Ingår i: Thromb Haemost. - 0340-6245. ; 91:5, s. 991-9
-
Tidskriftsartikel (refereegranskat)abstract
- Defensins, cationic peptides with bacteriolytic properties, are abundantly found at inflammation sites and in human coronary vessels. Vascular occlusive diseases, such as myocardial infarction, pulmonary embolism, and peripheral arterial occlusion are presently treated by thrombolytic intervention using staphylokinase, a plasminogen activator of bacterial origin. In this study we assessed a possible interaction between defensins and staphylokinase, both molecules being present in an acutely ill patient. Using an ELISA-based system, we found that staphylokinase and defensins displayed a strong and dose-dependent binding. In contrast, urokinase, another plasminogen activator of endogenous origin, displayed only minimal binding to defensins. Next, we proved that interaction between staphylokinase and defensins led to functional consequences resulting in a significant decrease (p<0.002) of plasminogen activation capacity upon complex formation. In contrast, urokinase retained most of its activity even in 10-fold molar excess of defensins. Finally, we found that staphylokinase-triggered lysis of fibrin was efficiently inhibited in the presence of defensins. To assess structural requirements for staphylokinase/defensin interaction, six staphylokinase mutant variants were studied. Inactivation pattern of the tested staphylokinase variants suggested a direct binding of defensins to serine protease-like domain of staphylokinase. In conclusion, we show complex formation between staphylokinase and alpha-defensins resulting in a significant reduction of fibrinolytic activity. This finding may have clinical implications, since fibrinolytic effects of staphylokinase may be downregulated at the site of vascular occlusion.
|
|
| 5. |
- Bokarewa, Maria, 1963, et al.
(författare)
-
Intraarticular release and accumulation of defensins and bactericidal/permeability-increasing protein in patients with rheumatoid arthritis.
- 2003
-
Ingår i: The Journal of rheumatology. - 0315-162X. ; 30:8, s. 1719-24
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Defensins and bactericidal/permeability-increasing protein (BPI) are the components of the azurophilic granules of polymorphonuclear cells (PMNC) maintaining antimicrobial protection. Both these substances have been suggested to interact with the host immune system rather than merely kill invading pathogens. We assessed concentrations of BPI and a-defensins in synovial fluid (SF) and matching blood samples of patients with rheumatoid arthritis (RA). METHODS: Matching samples of SF and blood were collected from 67 patients with RA (aged 21-73 yrs) with acute joint effusion. Blood samples from 22 healthy individuals made up a control group. Concentrations of BPI and human neutrophil peptides (HNP 1-3) were measured by ELISA. The results were related to radiological signs of destructive arthritis, duration of the disease, and laboratory markers of inflammation. RESULTS: BPI and HNP concentrations in SF were 10-60 times higher than in matching blood samples (p < 0.0001). Strong correlations between BPI and HNP concentrations were found in both blood and SF. In SF, BPI and HNP concentrations correlated to white blood cell (WBC) count (p < 0.001), and were associated with erosive joint disease (p < 0.05). In contrast, WBC count, serum C-reactive protein, or rheumatoid factor were not significantly correlated to the BPI or HNP concentrations. Serum BPI concentrations were moderately but significantly increased in RA patients compared in blood to controls (p < 0.05). CONCLUSION: BPI and HNP are accumulated in the synovial cavity of patients with RA. Significant correlation between joint erosion and local occurrence of BPI and HNP suggests participation of these molecules in regulation of the destructive course of RA.
|
|
| 6. |
- Bylund, Johan, 1975, et al.
(författare)
-
Immunostimulatory DNA induces degranulation and NADPH-oxidase activation in human neutrophils while concomitantly inhibiting chemotaxis and phagocytosis
- 2002
-
Ingår i: Eur J Immunol. ; 32:10, s. 2847-56
-
Tidskriftsartikel (refereegranskat)abstract
- We examined the effects of oligodeoxynucleotides (ODN) with different structures and sequences on human neutrophil function. In lymphocytes and monocytes, the CpG-mediated immunostimulation is dependent on motif content, flanking sequences and DNA backbone composition. In neutrophils, however, native phosphodiester ODN were without effect regardless of CpG content, while backbone-substituted phosphorothioate ODN (PS-ODN) modulated neutrophil function in a sequence-independent manner. The neutrophil respiratory burst and degranulation of the specific and gelatinase granules were markedly increased by PS-ODN, as was the shedding of L-selectin. In contrast, neutrophil chemotaxis and phagocytosis were inhibited by PS-ODN. In summary, PS-ODN have both stimulatory and inhibitory effects on neutrophil function. This impact of PS-ODN on neutrophil function is unique and distinct from that exerted on other immune cells, with respect to both the identity of the activating DNA molecules and the regulation of the effector functions. These findings may have implications for the development of DNA-based immunotherapy and vaccination.
|
|
| 7. |
- Calander, Ann-Marie, 1957, et al.
(författare)
-
Impact of staphylococcal protease expression on the outcome of infectious arthritis
- 2004
-
Ingår i: Microbes Infect. - : Elsevier BV. - 1286-4579. ; 6:2, s. 202-6
-
Tidskriftsartikel (refereegranskat)abstract
- The exoproteases of Staphylococcus aureus have been proposed as virulence factors during S. aureus infections. To investigate this, we used the wild-type S. aureus strain 8325-4 and its mutants devoid of aureolysin, serine protease, and cysteine protease, respectively, in a well-established model of septic arthritis in mice. The inactivation of the exoprotease genes did not affect the frequency or the severity of joint disease. We conclude that in the model of haematogenously spread staphylococcal arthritis, the bacterial proteases studied do not act as virulence factors.
|
|
| 8. |
- Carlsten, Hans, 1954, et al.
(författare)
-
The impact of a new immunomodulator oxo-quinoline-3-carboxamide on the progression of experimental lupus
- 2004
-
Ingår i: Int Immunopharmacol. - : Elsevier BV. - 1567-5769. ; 4:12, s. 1515-23
-
Tidskriftsartikel (refereegranskat)abstract
- Autoimmune, lupus-prone MRL lpr/lpr mice were treated orally with oxo-quinoline-3-carboxamide (ABR-25757), a newly developed immunomodulator. Treatment was initiated in one set of experiment at the age of 10 weeks, before the onset of clinically apparent disease, and in another set at 15 weeks, after the development of established lupus disease. Beneficial therapeutic effects were obtained even when ABR-25757 was administered at the lowest dose tested (7.5 microg/mouse/week) to 15 weeks old mice with established lupus disease. The effects of ABR-25757 on longevity, as well as on development of glomerulonephritis were pronounced and comparable with those of LS-2616, a potent immunomodulator. Administration of ABR-25757 did not significantly alter T cell responses in vivo nor in vitro. In addition, it only marginally suppressed B cell responses measured as frequencies of immunoglobulin secreting cells. By the same token this compound did not affect overall leukocyte content in primary (bone marrow) or secondary (spleen) lymphoid tissues. In contrast, treatment with ABR-25757 up regulated expression of pro-inflammatory transcription factors NF-kappaB and AP-1. These results suggest (a) a potential therapeutic role of ABR-25757 in the treatment of experimental lupus and (b) that the effect of the treatment is mediated by immunodeviation rather than by immunosuppression.
|
|
| 9. |
- Collins, Vincent, 1962, et al.
(författare)
-
Endogenously oxidized mitochondrial DNA induces in vivo and in vitro inflammatory responses
- 2004
-
Ingår i: J Leukoc Biol. - : Oxford University Press (OUP). - 0741-5400. ; 75:6, s. 995-1000
-
Tidskriftsartikel (refereegranskat)abstract
- We report that mitochondrial DNA (mtDNA) is inflammatogenic in vitro and in vivo as a result of the presence of unmethylated CpG sequences and its oxidative status. Purified human and murine mtDNAs induced arthritis when injected intra-articularly (i.a.) in mice. Importantly, oligodeoxynucleotide that contained a single oxidatively damaged base also induced arthritis when injected i.a. in mice. In contrast, neither human nor murine nuclear DNA induced inflammation. mtDNA-induced arthritis was neither B cell- nor T cell-dependent but was mediated by monocytes/macrophages. mtDNA-induced nuclear factor-kappaB stimulation resulted in the production of tumor necrosis factor alpha, a potent, arthritogenic factor. Finally, extracellular mtDNA was detected in the synovial fluids of rheumatoid arthritis patients but not of control subjects. We conclude that endogenous mtDNA displays inflammatogenic properties as a result of its content of unmethylated CpG motifs and oxidatively damaged adducts.
|
|
| 10. |
- Gjertsson, Inger, 1962, et al.
(författare)
-
Are B lymphocytes of importance in severe Staphylococcus aureus infections?
- 2000
-
Ingår i: Infection and immunity. - 0019-9567. ; 68:5, s. 2431-4
-
Tidskriftsartikel (refereegranskat)abstract
- To investigate the role of B cells in experimental, superantigen-mediated Staphylococcus aureus arthritis and sepsis, we used gene-targeted B-cell-deficient mice. The mice were inoculated intravenously with a toxic shock syndrome toxin 1 (TSST-1)-producing S. aureus strain. The B-cell-deficient and thus agamma-globulinemic mice showed striking similarities to the wild-type control animals with respect to the development of arthritis, the mortality rate, and the rate of bacterial clearance. Surprisingly, we found that the levels of gamma interferon in serum were significantly lower (P < 0. 0001) in B-cell-deficient mice than in the controls, possibly due to impaired superantigen presentation and a diminished expression of costimulatory molecules. In contrast, the levels of interleukin-4 (IL-4), IL-6, and IL-10 in serum were equal in both groups. Our findings demonstrate that neither mature B cells nor their products significantly contribute to the course of S. aureus-induced septic arthritis.
|
|
