| 1. |
- Dzhambazov, Balik, et al.
(författare)
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The major T cell epitope on type II collagen is glycosylated in normal cartilage but modified by arthritis in both rats and humans
- 2005
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Ingår i: European Journal of Immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 35:2, s. 357-366
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Tidskriftsartikel (refereegranskat)abstract
- Type II collagen (CII) is a target for autoreactive T cells in both rheumatoid arthritis and the murine model collagen-induced arthritis. The determinant core of CII has been identified as CII260-270, and the alteration of this T cell epitope by posttranslational modifications is known to be critical for development of arthritis in mice. Using CII-specific T cell hybridomas we have now shown that the immunodominant T cell epitope in the normal (healthy) human and rat joint cartilage is O-glycosylated at the critical T cell receptor recognition position 264 with a mono- or di-saccharide attached to a hydroxylysine. In contrast, in the arthritic human and rat joint cartilage there are both glycosylated and non-glycosylated CII forms. Glycosylated CII from normal cartilage could not be recognized by T cells reactive to peptides having only lysine or hydroxylysine at position 264, showing that antigen-presenting cells could not degrade the O-linked carbohydrate. Thus, the variable forms of the glycosylated epitope are determined by the structures present in cartilage, and these vary during the disease course. We conclude that the chondrocyte determines the structures presented to the immune system and that these structures are different in normal versus arthritic states.
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| 2. |
- Andersson, Ida E, 1982-, et al.
(författare)
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Design of glycopeptides used to investigate class II MHC binding and T-Cell responses associated with autoimmune arthritis
- 2011
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 6:3, s. e17881-
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Tidskriftsartikel (refereegranskat)abstract
- The glycopeptide fragment CII259–273 from type II collagen (CII) binds to the murine Aq and human DR4 class II Major Histocompatibility Complex (MHC II) proteins, which are associated with development of murine collagen-induced arthritis (CIA) and rheumatoid arthritis (RA), respectively. It has been shown that CII259–273 can be used in therapeutic vaccination of CIA. This glycopeptide also elicits responses from T-cells obtained from RA patients, which indicates that it has an important role in RA as well. We now present a methodology for studies of (glyco)peptide-receptor interactions based on a combination of structure-based virtual screening, ligand-based statistical molecular design and biological evaluations. This methodology included the design of a CII259–273 glycopeptide library in which two anchor positions crucial for binding in pockets of Aq and DR4 were varied. Synthesis and biological evaluation of the designed glycopeptides provided novel structure-activity relationship (SAR) understanding of binding to Aq and DR4. Glycopeptides that retained high affinities for these MHC II proteins and induced strong responses in panels of T-cell hybridomas were also identified. An analysis of all the responses revealed groups of glycopeptides with different response patterns that are of high interest for vaccination studies in CIA. Moreover, the SAR understanding obtained in this study provides a platform for the design of second-generation glycopeptides with tuned MHC affinities and T-cell responses.
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| 3. |
- Andersson, Ida E., 1982-, et al.
(författare)
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(E)-Alkene and Ethylene Isosteres Substantially Alter the Hydrogen-Bonding Network in Class II MHC Aq/Glycopeptide Complexes and Affect T-Cell Recognition
- 2011
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society. - 0002-7863 .- 1520-5126. ; 133:36, s. 14368-14378
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Tidskriftsartikel (refereegranskat)abstract
- The structural basis for antigen presentation by class II major histocompatibility complex (MHC) proteins to CD4(+) T-cells is important for understanding and possibly treating autoimmune diseases. In the work described in this paper, (E)-alkene and ethylene amide-bond isosteres were used to investigate the effect of removing hydrogen-bonding possibilities from the CII259-270 glycopeptide, which is bound by the arthritis-associated murine A(q) class II MHC protein. The isostere-modified glycopeptides showed varying and unexpectedly large losses of A(q) binding that could be linked to the dynamics of the system. Molecular dynamics (MD) simulations revealed that the backbone of CII259-270 and the A(q) protein are able to form up to 11 hydrogen bonds, but fewer than this number are present at any one time. Most of the strong hydrogen-bond interactions were formed by the N-terminal part of the glycopeptide, i.e., in the region where the isosteric replacements were made. The structural dynamics also revealed that hydrogen bonds were strongly coupled to each other; the loss of one hydrogen-bond interaction had a profound effect on the entire hydrogen-bonding network. The A(q) binding data revealed that an ethylene isostere glycopeptide unexpectedly bound more strongly to A(q) than the corresponding (E)-alkene, which is in contrast to the trend observed for the other isosteres. Analysis of the MD trajectories revealed that the complex conformation of this ethylene isostere was structurally different and had an altered molecular interaction pattern compared to the other A(q)/glycopeptide complexes. The introduced amide-bond isosteres also affected the interactions of the glycopeptide/A(q) complexes with T-cell receptors. The dynamic variation of the patterns and strengths of the hydrogen-bond interactions in the class II MHC system is of critical importance for the class II MHC/peptide/TCR signaling system.
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| 4. |
- Andersson, Ida E., 1982-, et al.
(författare)
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Oxazole-modified glycopeptides that target arthritis-associated class II MHC Aq and DR4 proteins
- 2010
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Ingår i: Organic and biomolecular chemistry. - : RSC Publishing. - 1477-0520 .- 1477-0539. ; 8:13, s. 2931-2940
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Tidskriftsartikel (refereegranskat)abstract
- The glycopeptide CII259-273, a fragment from type II collagen (CII), can induce tolerance in mice susceptible to collagen-induced arthritis (CIA), which is a validated disease model for rheumatoid arthritis (RA). Here, we describe the design and synthesis of a small series of modified CII259-273 glycopeptides with oxazole heterocycles replacing three potentially labile peptide bonds. These glycopeptidomimetics were evaluated for binding to murine CIA-associated A(q) and human RA-associated DR4 class II major histocompatibility complex (MHC) proteins. The oxazole modifications drastically reduced or completely abolished binding to A(q). Two of the glycopeptidomimetics were, however, well tolerated in binding to DR4 and they also induced strong responses by one or two DR4-restricted T-cell hybridomas. This work contributes to the development of an altered glycopeptide for inducing immunological tolerance in CIA, with the long-term goal of developing a therapeutic vaccine for treatment of RA.
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| 5. |
- Andersson, Ida E., 1982-, et al.
(författare)
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Probing Molecular Interactions within Class II MHC A(q)/Glycopeptide/T-Cell Receptor Complexes Associated with Collagen-Induced Arthritis.
- 2007
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 1520-4804 .- 0022-2623. ; 50:23, s. 5627-5643
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Tidskriftsartikel (refereegranskat)abstract
- T cells obtained in a mouse model for rheumatoid arthritis are activated by a glycopeptide fragment from rat type II collagen (CII) bound to the class II major histocompatibility complex A(q) molecule. We report a comparative model of A(q) in complex with the glycopeptide CII260-267. This model was used in a structure-based design approach where the amide bond between Ala(261) and Gly(262) in the glycopeptide was selected for replacement with psi[COCH2], psi[CH2NH2+], and psi[(E)-CH=CH] isosteres. Ala-Gly isostere building blocks were then synthesized and introduced in CII260-267 and CII259-273 glycopeptides. The modified glycopeptides were evaluated for binding to the A(q) molecule, and the results were interpreted in view of the A(q)/glycopeptide model. Moreover, recognition by a panel of T-cell hybridomas revealed high sensitivity for the backbone modifications. These studies contribute to the understanding of the interactions in the ternary A(q)/glycopeptide/T-cell receptor complexes that activate T cells in autoimmune arthritis and suggest possibilities for new vaccination approaches.
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| 6. |
- Dzhambazov, Balik, et al.
(författare)
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Therapeutic vaccination of active arthritis with a glycosylated collagen type II peptide in complex with MHC class II molecules
- 2006
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Ingår i: Journal of Immunology. - Rockville, MD : American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 176, s. 1525-33
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Tidskriftsartikel (refereegranskat)abstract
- In both collagen-induced arthritis (CIA) and rheumatoid arthritis, T cells recognize a galactosylated peptide from type II collagen (CII). In this study, we demonstrate that the CII259-273 peptide, galactosylated at lysine 264, in complex with Aq molecules prevented development of CIA in mice and ameliorated chronic relapsing disease. In contrast, nonglycosylated CII259-273/Aq complexes had no such effect. CIA dependent on other MHC class II molecules (Ar/Er) was also down-regulated, indicating a bystander vaccination effect. T cells could transfer the amelioration of CIA, showing that the protection is an active process. Thus, a complex between MHC class II molecules and a posttranslationally modified peptide offers a new possibility for treatment of chronically active autoimmune inflammation such as rheumatoid arthritis. © 2006 by The American Association of Immunologists, Inc.
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| 7. |
- Dzhambazov, Balik, et al.
(författare)
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Tissue transglutaminase enhances collagen type II-induced arthritis and modifies the immunodominant T-cell epitope CII260-270
- 2009
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 39:9, s. 2412-2423
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Tidskriftsartikel (refereegranskat)abstract
- The calcium-dependent enzyme tissue transglutaminase (tTG) is associated with diverse biological functions, such as induction of apoptosis, modeling of the extracellular matrix, receptor-mediated endocytosis, cell growth and differentiation, cell adhesion and signal transduction. Also, it may deamidate glutamine residues to glutamic acid and catalyze cross-linking of proteins. In this study, we have investigated the impact of tTG for posttranslational modifications and cross-linking of the immunodominant T-cell epitope CII260-270 and their effects on the collagen-induced arthritis, an animal model for rheumatoid arthritis. By using mass spectrometry analysis and hybridoma assays, we have demonstrated that tTG could perform both types of modifications (deamidation and cross-link formation) on the immunodominant T-cell epitope CII259-273. Replacement of the glutamine at position 267 with glutamic acid leads to a decreased binding affinity to MHC II. T cells recognized both non-modfied (Q(267)) and modified (E(267)) CII259-273-peptides. We also show that administration of tTG leads to increased incidence, severity and histopathological manifestations of collagen-induced arthritis in mice. Moreover, we conclude that both processes, deamidation and cross-linking, are involved in the tTG-catalyzed reactions, and in vivo administration of tTG enhances arthritis severity and joint destruction in mice.
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| 8. |
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| 9. |
- Holm, Lotta, et al.
(författare)
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Quantitative Structure-Activity Relationship of Peptides Binding to the Class II Major Histocompatibility Complex Molecule A(q) Associated with Autoimmune Arthritis.
- 2007
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 1520-4804 .- 0022-2623. ; 50:9, s. 2049-2059
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Tidskriftsartikel (refereegranskat)abstract
- Presentation of (glyco)peptides by the class II major histocompatibility complex molecule Aq to T cells plays a central role in collagen-induced arthritis, an animal model for the autoimmune disease rheumatoid arthritis. A peptide library was designed using statistical molecular design in amino acid space in which five positions in the minimal mouse collagen type II binding epitope CII260-267 were varied. A substantially reduced peptide library of 24 peptides with diverse and representative molecular characteristics was selected, synthesized, and evaluated for the binding strength to Aq. A multivariate QSAR model was established by correlating calculated descriptors, compressed to its principle properties, with the binding data using partial least-square regression. The model was successfully validated by an external test set. Interpretation of the model provided a molecular property binding motif for peptides interacting with Aq. The information may be useful in future research directed toward new treatments of rheumatoid arthritis.
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| 10. |
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