| 1. |
- Ahrén, Irini Lazou, et al.
(författare)
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The importance of a β-glucan receptor in the nonopsonic entry of nontypeable Haemophilus influenzae into human monocytic and epithelial cells
- 2001
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 0022-1899 .- 1537-6613. ; 184:2, s. 150-158
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Tidskriftsartikel (refereegranskat)abstract
- Previous reports showed that nontypeable Haemophilus influenzae (NTHi) reside in macrophage-like cells in human adenoid tissue. This study investigated the ability of nonopsonized NTHi and encapsulated H. influenzae type b (Hib) to enter human monocytic and epithelial cells. The number of intracellular bacteria was determined by a viability assay and flow cytometry. To characterize the mechanisms responsible for the internalization of NTHi, different inhibitors of surface molecules, receptor turnover, and the cytoskeleton were used. Hib were found in monocytic cells at very low numbers (<100 bacteria/2 × 105 cells). In contrast, a great variation in intracellular numbers was detected between the different NTHi isolates (range, 0.0007%-0.28% of the inoculum for monocytes and 0.053%-3.5% for epithelial cells). NTHi entered human monocytic and epithelial cells via a receptor-mediated endocytosis involving mainly a β-glucan receptor that could be blocked by laminarin.
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| 2. |
- Ahren, IL, et al.
(författare)
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Nontypeable Haemophilus influenzae activates human eosinophils through beta-glucan receptors
- 2003
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Ingår i: American Journal of Respiratory Cell and Molecular Biology. - 1535-4989. ; 29:5, s. 598-605
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Tidskriftsartikel (refereegranskat)abstract
- Eosinophils are a characteristic component of the inflammatory response seen in several diseases, including allergic asthma and chronic obstructive pulmonary disease. After activation, eosinophil-derived products may exert proinflammatory effects and cause considerable tissue damage. In the present study, we investigated innate interactions between the respiratory tract pathogen nontypeable Haemophilus influenzae (NTHi) and human eosinophils. Bacterial binding to eosinophils was dependent on (1-3)-beta-D-glucan receptors, as deduced from blocking experiments using the soluble glucan derivatives laminarin and scleroglucan. In addition, expression of the beta-glucan receptor dectin-1 was shown in eosinophils by reverse transcriptase-polymerase chain reaction. Activation of the beta-glucan receptors by bacteria elicited a time- and dose-dependent respiratory burst in eosinophils. NTHi caused increased expression of the proinflammatory chemokine interleukin-8 as measured by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay. Incubation of eosinophils in the presence of NTHi for 4.5 h revealed upregulation of 245 different genes as detected by microarray. Signal transduction-related transcripts were most strongly upregulated, followed by cytokine mRNAs. Our findings suggest that NTHi can induce an innate inflammatory response in eosinophils that is mainly mediated via beta-glucan receptors. This points to possible pathophysiologic mechanisms involving innate recognition of NTHi by eosinophils during infection of the airways, thus promoting inflammation in chronic pulmonary disease.
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| 3. |
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| 4. |
- Bråbäck, Martin, et al.
(författare)
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Susceptibilities of Mycobacterium marinum to Gatifloxacin, Gemifloxacin, Levofloxacin, Linezolid, Moxifloxacin, Telithromycin, and Quinupristin-Dalfopristin (Synercid) Compared to Its Susceptibilities to Reference Macrolides and Quinolones.
- 2002
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Ingår i: Antimicrobial Agents and Chemotherapy. - 1098-6596. ; 46:4, s. 1114-1116
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Tidskriftsartikel (refereegranskat)abstract
- The susceptibility pattern of Mycobacterium marinum was determined. Quinupristin-dalfopristin and telithromycin were less active than clarithromycin. Linezolid showed good antimicrobial activity at clinically achievable concentrations. Gatifloxacin, levofloxacin, and moxifloxacin displayed activities similar to those of ciprofloxacin. Gemifloxacin was less active. The Etest method showed variable agreement with the reference method.
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| 5. |
- Corbascio, Matthias, et al.
(författare)
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CTLA4Ig combined with anti-LFA-1 prolongs cardiac allograft survival indefinitely.
- 2002
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Ingår i: Transplant Immunology. - 1878-5492. ; 10:1, s. 55-61
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Tidskriftsartikel (refereegranskat)abstract
- CTLA4Ig and anti-LFA-1 are members of a new generation of immunomodulatory drugs which inhibit important signaling pathways in T cell activation. Both substances target molecules which have pivitol functions in the activation of CD4+ and CD8+ T cells and have been theorized to have an interdependent relationship. These drugs have been used independently in various treatment regimens and have shown great promise in prolonging the survival of allografts. In order to test whether these substances have synergistic or potentiating effects when combined, we performed mixed lymphocyte reactions, skin transplantation and vascularised heterotopic heart transplantation in the Balb/c (H-2(d)) to C3H/HeJ (H-2(k)) strain combination. When anti-LFA-1 and CTLA4Ig were combined at low doses, there was a substantial inhibition of lymphocyte proliferation. When each drug was used as a mono-therapy in skin graft recipients, there was no significant effect on median graft survival (anti-LFA-1, 15 days; CTLA4Ig, 16 days) when compared to untreated controls (13 days), whereas a combination of anti-LFA-1 and CTLA4Ig extended graft survival significantly to 32 days. Untreated vascularised heart grafts rejected at a median of 8 days, CTLA4Ig-treated mice rejected at a median time of 79 days and anti-LFA-1-treated mice rejected at 43 days (n = 9). When CTLA4Ig and anti-LFA-1 were combined, all animals had functioning heart grafts at 100 days after transplantation. Histological analysis of combined-therapy hearts showed no signs or only minor changes associated with chronic rejection. In conclusion, these results indicate a synergistic effect of combining anti-LFA-1 with CTLA4Ig in inhibiting lymphocyte proliferation and prolonging the survival of fully MHC-mismatched allografts.
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| 6. |
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| 7. |
- Forsgren, Arne, et al.
(författare)
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Isolation and characterization of a novel IgD-binding protein from Moraxella catarrhalis
- 2001
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Ingår i: Journal of Immunology. - 1550-6606. ; 167:4, s. 2112-2120
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Tidskriftsartikel (refereegranskat)abstract
- A novel surface protein of the bacterial species Moraxella catarrhalis that displays a high affinity for IgD (MID) was solubilized in Empigen and isolated by ion exchange chromatography and gel filtration. The apparent molecular mass of monomeric MID was estimated to approximately 200 kDa by SDS-PAGE. The mid gene was cloned and expressed in Escherichia coli. The complete mid nucleotide gene sequence was determined, and the deduced amino acid sequence consists of 2123 residues. The sequence of MID has no similarity to other Ig-binding proteins and differs from all previously described outer membrane proteins of M. catarrhalis. MID was found to exhibit unique Ig-binding properties. Thus, in ELISA, dot blots, and Western blots, MID bound two purified IgD myeloma proteins, four IgD myeloma sera, and finally one IgD standard serum. No binding of MID was detected to IgG, IgM, IgA, or IgE myeloma proteins. MID also bound to the surface-expressed B cell receptor IgD, but not to other membrane molecules on human PBLs. This novel Ig-binding reagent promises to be of theoretical and practical interest in immunological research.
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| 8. |
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| 9. |
- Gjörloff Wingren, Anette, et al.
(författare)
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The novel IgD binding protein from Moraxella catarrhalis induces human B lymphocyte activation and Ig secretion in the presence of Th2 cytokines.
- 2002
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Ingår i: Journal of Immunology. - 1550-6606. ; 168:11, s. 5582-5588
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Tidskriftsartikel (refereegranskat)abstract
- Moraxella IgD binding protein (MID) is a novel bacterial outer membrane protein with IgD-binding properties. MID was purified from the respiratory pathogen Moraxella catarrhalis and is here shown to have B cell stimulatory properties. Purified MID in the range of 0.01-0.1 microg/ml was optimal to induce a proliferative response in human PBL. MID coupled to Sepharose and formalin-fixed M. catarrhalis preparations induced similar proliferative responses in PBL cultures. MID or MID-Sepharose stimulated purified human peripheral B cells as measured by proliferation. In contrast, MID or MID-Sepharose did not activate T cells. Preincubation of purified B cells with anti-IgD Abs inhibited MID-Sepharose-induced B cell proliferation. The addition of IL-4 specifically induced IL-6 production in MID-Sepharose-activated B cells. IgM secretion was detected in B cell cultures stimulated with MID or MID-Sepharose and IL-2 for 10 days. Secretion of IgG and IgA was efficiently induced in cultures from purified B cells stimulated with the combination of MID or MID-Sepharose and IL-4, IL-10, and soluble CD40 ligand, suggesting that Th2-derived cytokines were required for optimal plasma cell generation. Taken together, MID has properties that make it an important tool to study IgD-targeted activation of B cells.
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| 10. |
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