| 41. |
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| 42. |
- 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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| 43. |
- Bjursten, Malin, 1976, et al.
(författare)
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Long-term treatment with anti-alpha 4 integrin antibodies aggravates colitis in G alpha i2-deficient mice.
- 2005
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Ingår i: European journal of immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 35:8, s. 2274-83
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Tidskriftsartikel (refereegranskat)abstract
- Targeted deletion of the heterotrimeric G protein, Galphai2, in mice induces lethal colitis closely resembling ulcerative colitis. In chronic colitis, migration of circulating leukocytes into the intestinal mucosa is partially dependent on alpha4 integrins. In previous studies, short-term administration of anti-alpha4 integrin antibodies has been shown to attenuate intestinal inflammation, and here we elucidate the effect of long-term administration of anti-alpha4 integrin antibodies on colitis in Galphai2(-/- )mice. Long-term blockade of alpha4 integrin significantly increased the severity of colitis in Galphai2(-/-) mice. The inflammation was confined to the colon, associated with increased cancer in situ, destruction of crypt architecture, and increased production of IL-1beta, TNF-alpha and IFN-gamma. Blockade of alpha4 integrin reduced the recruitment of activated T cells to the small intestine. In strong contrast, there were significantly higher numbers of activated T cells in the colonic lamina propria and epithelium, most probably due to in situ proliferation. Furthermore, treatment with alpha4 integrin antibodies induced decreased levels of total IgA and IgG in sera, whereas total IgM levels were unchanged. These new findings may have implications in the understanding of the progression of chronic intestinal inflammation.
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| 44. |
- Blom, Thomas, et al.
(författare)
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Phenotypic characterization of KU812, a cell line identified as an immature human basophilic leukocyte
- 1992
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 22:8, s. 2025-2032
-
Tidskriftsartikel (refereegranskat)abstract
- The knowledge about the differentiation of basophilic leukocytes is fragmentary. This report discusses a detailed phenotypic characterization of molecular markers for hematopoietic differentiation in a basophilic leukemia cell line, KU812. The expression of markers for lymphoid, erythroid, neutrophil, eosinophil, monocytic, megakaryocytic, mast cell and basophil differentiation was analyzed at the mRNA level by Northern blots in the KU812 cells, and for reference, in a panel of human cell lines representative of the different hematopoietic differentiation lineages. KU812 was found to express a number of mast cell and basophil-related proteins, i.e. mast cell tryptase, mast cell carboxypeptidase A, high-affinity immunoglobulin (IgE) receptor α and γ chains and the core protein for heparin and chondroitin sulphate synthesis. We found no expression of a number of monocyte/-macrophage or neutrophil leukocyte markers except for lysozyme. From earlier studies, it has been shown that lysozyme is not expressed in murine mucosal mast cell lines. This finding, together with the expression of the mast cell carboxypeptidase in KU812 might distinguish the phenotype of this cell line from that typical of mucosal mast cell lines in rodents. We found a low level of expression of the eosinophil and basophil marker, major basic protein, which might indicate a relationship between basophils and eosinophils. No expression is, however, detected with the eosinophil-specific markers, eosinophil cationic protein, eosinophil-derived neurotoxin or eosinophil peroxidase. We also report an extensive screening for inducers of basophilic differentiation of the KU812 cells. The most efficient protocol of induction included serum starvation which led to a dramatic increase in a number of markers specific for mast cells and basophils such as tryptase, carboxypeptidase A and the heparin core protein. Finally, diisopropylfluorophosphate analysis of total protein extracts from KU812 show four labeled protein bands with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that this cell line expresses at least three previously undescribed serine proteases of which one or more could be a potential basophil-specific marker(s).
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| 45. |
- Blomqvist, Maria K., 1975, et al.
(författare)
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Multiple tissue-specific isoforms of sulfatide activate CD1d-restricted type II NKT cells.
- 2009
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Ingår i: European journal of immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 39:7, s. 1726-35
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Tidskriftsartikel (refereegranskat)abstract
- The glycosphingolipid sulfatide (SO(3)-3Galbeta1Cer) is a demonstrated ligand for a subset of CD1d-restricted NKT cells, which could regulate experimental autoimmune encephalomyelitis, a murine model for multiple sclerosis, as well as tumor immunity and experimental hepatitis. Native sulfatide is a mixture of sulfatide isoforms, i.e. sulfatide molecules with different long-chain bases and fatty acid chain lengths and saturation. Here, we demonstrate that sulfatide-specific CD1d-restricted murine NKT hybridomas recognized several different sulfatide isoforms. These included the physiologically relevant isoforms C24:1 and C24:0, major constituents of the myelin sheet of the nervous system, and C16:0, prominent in the pancreatic islet beta-cells. The most potent sulfatide isoform was lysosulfatide (lacking a fatty acid). Shortened fatty acid chain length (C24:1 versus C18:1), or saturation of the long fatty acid (C24:0), resulted in reduced stimulatory capacity, and fatty acid hydroxylation abolished the response. Moreover, sulfatide was not responsible for the natural autoreactivity toward splenocytes by XV19 T hybridoma cells. Our results reveal a promiscuity in the recognition of sulfatide isoforms by a CD1d-restricted NKT-cell clone, and suggest that sulfatide, a major component of the myelin sheet and pancreatic beta-cells, is one of several natural ligands for type II CD1d-restricted NKT cells.
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| 46. |
- Bockermann, Robert, et al.
(författare)
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Type II collagen without adjuvant induces eosinophilic arthritis.
- 2007
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Ingår i: European Journal of Immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 37:2, s. 540-548
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Tidskriftsartikel (refereegranskat)abstract
- Eosinophilia is a characteristic feature of many inflammatory diseases including inflammatory bowel disease and asthma. It also occurs in a subtype of rheumatoid arthritis but the role of eosinophils has been unclear and animal models have been lacking. Here, we introduce a new mouse model to study the role of eosinophilia in arthritis. Intraperitoneal injection of type II collagen alone, without any adjuvant, was sufficient to induce chronic arthritis in a mouse with transgenic T cells specific for type II collagen. The arthritis was accompanied by infiltration of eosinophils into the synovial tissue and the disease could be blocked with neutralizing anti-IL-5 antibodies. To our knowledge, this is the first description of an eosinophilic disease form of destructive arthritis.
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| 47. |
- Boeiers, Ulrika, et al.
(författare)
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Collagen type II is recognized by a pathogenic antibody through germline encoded structures
- 2008
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Ingår i: European Journal of Immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 38:10, s. 2784-2795
-
Tidskriftsartikel (refereegranskat)abstract
- Collagen type II (CII) is a cartilage-specific target of pathologic humoral autoimmune responses in rheumatoid arthritis as well as in the collagen-induced arthritis model. The aim of the present study is to investigate the critical amino acid residues conferring CII epitope specificity of the prototypic arthritogenic murine mAb CIIC1. A homology model of the CIIC1 single-chain antibody fragment (CIIC1scFv) in complex with its triple helical epitope was established. in silico predictions based on extensive molecular dynamics simulations were experimentally tested by the recombinant expression and functional analysis of CIIC1scFv containing alanine replacements allowing the identification of crucial CII-binding sites in the CDR2 and CDR3 regions of both heavy and light chains. Since the conversion of the CIIC1scFv sequence into the respective germline at all 13 somatically mutated positions did not affect its CII binding, our data indicate that potentially harmful cartilage-specific humoral autoimmunity could be germline encoded. The molecular modeling further demonstrates that the rigid collagen triple helix restricts the likelihood of molecular interactions with the CDR regions of the antibody considerably compared with globular antigens. These sterical constraints provide an explanation as to why somatic mutations in the arthritogenic autoantibody have no obvious impact on CII recognition.
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| 48. |
- Bokarewa, Maria, 1963, et al.
(författare)
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Arthritogenic dsRNA is present in synovial fluid from rheumatoid arthritis patients with an erosive disease course.
- 2008
-
Ingår i: European journal of immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 38:11, s. 3237-44
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Tidskriftsartikel (refereegranskat)abstract
- Viruses may be part of the pathogenesis of rheumatoid arthritis (RA). Double stranded RNA (dsRNA) is a prototypic viral conformation of nucleic acid that is highly arthritogenic in mice. Therefore, we developed an ELISA to detect dsRNA in sera and synovial fluids (SF) in RA patients and in osteoarthritic controls. The developed ELISA recognizes picogram levels of viral or synthetic dsRNA but shows no reactivity against DNA, synthetic ssRNA, or total RNA prepared from mammalian cells. Before analysis by ELISA, each sample was subjected to RNA precipitation. The RA patients had significantly higher levels of dsRNA than the osteoarthritis patients in SF and in sera. In 7 of 17 RA patients, EBV was present in SF and in all but one of these this was accompanied by the presence of dsRNA. No parvovirus, cytomegalovirus, or polyomavirus was detected. The anti-viral cytokine IFN-alpha was detected in SF in 10 of 21 RA patients, but in none of the osteoarthritis patients. Notably, RA patients with erosive disease course had significantly higher levels of dsRNA in SF than non-erosive patients, but no correlation between dsRNA levels and the presence of RF or levels of C-reactive protein, IL-6, or IFN-alpha was observed.
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| 49. |
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| 50. |
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