Development of an I-Ag7-expressing Antigen-presenting Cell Line: Intrinsic Molecular Defect in Compact I-Ag7Dimer Generation

Nabavieh, Ali; Chou, Henry; Volokhov, Irina; Lee, James E.; Purdy, Lisa; Elliott, John F.; Singh, Bhagirath; Madrenas, Joaquı́n

doi:10.1006/jaut.1997.0176

Cited by 8 publications

(6 citation statements)

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“…Several peptides isolated from H2‐A g7 with acidic residues at p9 and p10/11 bind to H2‐A g7 , presumably in the same register, with an IC 50 that is 4‐ to 28‐times greater at pH 7–7.5 than at pH 5.5 9, 37. The H2‐A g7 molecule is unstable upon SDS treatment in vitro 5, 9, 11, 15, 16 and in vivo 5, 11. It is the only known MHC class II allele in which the continuous presence of certain antigenic peptides was required for cognate T cell proliferation, while in other alleles 5 min of pulsing with peptide and subsequent washing of APC was sufficient to insure T cell response 5, 9.…”

Section: Discussionmentioning

confidence: 99%

“…Under reducing conditions several laboratories have shown that H2‐A g7 and H2‐A d are highly sensitive to SDS treatment, with less than 1% and 5% of the respective molecules remaining in compact dimer form, while the u, k, s and b alleles range from 50–90% 5, 8, 9, 11. H2‐A d and H2‐A g7 are the only two MHC class II alleles with the small‐sized Ala at β78 29, next to the only disulfide bond in the α1β1 domain of such molecules, and are expected to permit the ready reduction of this bond.…”

Section: Discussionmentioning

confidence: 99%

“…Conflicting properties have been attributed to the H2‐A g7 allele: the molecule is either a very weak and non‐selective binder of antigenic peptides 4–6, or has contrasting binding motifs, particularly for positions 6 and 9 7–10. There is a consensus that H2‐A g7 does not form SDS‐stable complexes in the presence of antigenic peptides 5, 9, 11. The diabetes‐susceptible MHC class II molecules in mouse, rat, and human generally lack an Asp in position β57 1–3.…”

Section: Introductionmentioning

confidence: 99%

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Peptide analysis, stability studies, and structural modeling explain contradictory peptide motifs and unique properties of the NOD mouse MHC class II molecule H2-Ag7

et al. 2002

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The MHC class II molecule H2‐Ag7 is the chief genetic determinant in insulin‐dependent diabetes mellitus of the non‐obese diabetic (NOD) mice. Poor peptide binding ability, as well aspresentation of a unique subset of peptides by this molecule was suggested to promote autoimmunity in this strain. However, several laboratories have presented results in favor of an H2‐Ag7 molecule that can avidly bind many different peptides. The crystal structures of H2‐Ag7 in complex with two different peptides did not completely resolve this issue. To analyze the peptide binding capacity and the motif requirements of H2‐Ag7, we eluted natural ligands from purified H2‐Ag7 molecules isolated from the H2‐Ag7‐transfected M12‐C3 cells. A low peptide yield dominated by a few peptide ligands was found. Pool sequencing and alignment of individual ligands on the basis of molecular modeling revealed a peptide‐binding motif with basic/aliphatic/small hydrophilic amino acids at relative position 1 (p1), aliphatic amino acids at p4, Ala at p6, and acidic amino acids and Ser/Gly at p9, as well as acidic residues at p10/11. Though weak, the binding of individual ligands, as well as the importance of an acidic C‐terminal residue was confirmed by peptide binding studies to isolated H2‐Ag7 molecules. Furthermore, the H2‐Ag7 molecule incompletely dissociated into its constituent chains in SDS‐electrophoresis under nonreducing conditions. This provides additional evidence of its weak affinity for peptides, which probably arises from the combination of β56His/β57Ser/β78Ala and other unique H2‐Ag7 residues in contact with the antigenic peptide. These results allow a better understanding of the role of this molecule in the development of autoimmunity and the identification of epitopes relevant to diabetes.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Peptide analysis, stability studies, and structural modeling explain contradictory peptide motifs and unique properties of the NOD mouse MHC class II molecule H2-Ag7

et al. 2002

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“…DAPg7 fibroblastic cells (I-A g7 H2-K k ) 51 were donated by Dr. Elisabeth Mellins (Stanford University). PCRC-5 cells are NOD lymph node SCs immortalized in our lab by overexpression of human papilloma virus E6/E7 proteins.…”

Section: Methodsmentioning

confidence: 99%

Efficient Presentation of Multiple Endogenous Epitopes to Both CD4 + and CD8 + Diabetogenic T Cells for Tolerance

Dastagir

Postigo-Fernandez

et al. 2017

Molecular Therapy - Methods & Clinical Development

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Antigen-specific immunotherapy of type 1 diabetes, typically via delivery of a single native β cell antigen, has had little clinical benefit to date. With increasing evidence that diabetogenic T cells react against multiple β cell antigens, including previously unappreciated neo-antigens that can be emulated by mimotopes, a shift from protein- to epitope-based therapy is warranted. To this end, we aimed to achieve efficient co-presentation of multiple major epitopes targeting both CD4+ and CD8+ diabetogenic T cells. We have compared native epitopes versus mimotopes as well as various targeting signals in an effort to optimize recognition by both types of T cells in vitro. Optimal engagement of all T cells was achieved with segregation of CD8 and CD4 epitopes, the latter containing mimotopes and driven by endosome-targeting signals, after delivery into either dendritic or stromal cells. The CD4+ T cell responses elicited by the endogenously delivered epitopes were comparable with high concentrations of soluble peptide and included functional regulatory T cells. This work has important implications for the improvement of antigen-specific therapies using an epitope-based approach to restore tolerance in type 1 diabetes and in a variety of other diseases requiring concomitant targeting of CD4+ and CD8+ T cells.

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“…IL‐2 was quantified in culture supernatants by a standard enzyme‐linked immunosorbent assay (ELISA) (36). Briefly, 100 μl of anti‐mouse IL‐2 (PharMingen) was coated overnight at 4°C, and after blocking the wells, IL‐2 standard or IL‐2 from 100 μl of the culture supernatants (diluted 1:2) was captured overnight at 4°C.…”

Section: Methodsmentioning

confidence: 99%

CTLA‐4Ig blocks the development and progression of citrullinated fibrinogen–induced arthritis in DR4‐transgenic mice

Yue¹,

Brintnell²,

Mannik³

et al. 2010

Arthritis & Rheumatism

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Objective. To assess the role of T cells in the mouse model of citrullinated human fibrinogeninduced rheumatoid arthritis (RA) using CTLA-4Ig, an agent that blocks T cell costimulation, which is required for T cell activation.Methods. Humanized HLA-DR␤1*0401-transgenic (DR4-Tg) mice were immunized with Cithuman fibrinogen to induce arthritis. Prior to, and at the onset or peak of, arthritis, the DR4-Tg mice were treated with CTLA-4Ig or control human IgG1 or were left untreated. Arthritis development and progression were monitored by measuring ankle swelling with calipers and by assessing histopathologic changes. The immune responses to the citrullinated antigens and the corresponding unmodified antigens, as well as the arthritogenicity of lymphocytes from these mice, were examined. The latter was performed using lymphocyte transfers from CTLA-4Ig-treated or control mice via intraperitoneal injection into naive DR4-Tg mice. Recipient mice also received an intraarticular injection of Cit-human fibrinogen, unmodified human fibrinogen, or vehicle.Results. CTLA-4Ig-treated, but not human IgG1-treated, arthritic mice had significantly reduced ankle swelling and pathologic joint damage. Treatment with CTLA-4Ig, but not human IgG1, suppressed Cit-human fibrinogen-induced T cell activation, including citrulline-specific T cell activation, when given prior to disease onset. Transfer of splenic lymphocytes from untreated or human IgG1-treated arthritic mice caused arthritis in recipients, and this occurred when Cithuman fibrinogen, but not unmodified fibrinogen, was deposited into the joint. Splenocytes from CTLA-4Ig-treated mice were unable to transfer arthritis.Conclusion. Activated citrulline-specific T cells play a direct role in the development and progression of arthritis in this model of Cit-human fibrinogeninduced RA.

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Development of an I-Ag7-expressing Antigen-presenting Cell Line: Intrinsic Molecular Defect in Compact I-Ag7Dimer Generation

Cited by 8 publications

References 50 publications

Peptide analysis, stability studies, and structural modeling explain contradictory peptide motifs and unique properties of the NOD mouse MHC class II molecule H2-Ag7

Peptide analysis, stability studies, and structural modeling explain contradictory peptide motifs and unique properties of the NOD mouse MHC class II molecule H2-Ag7

Efficient Presentation of Multiple Endogenous Epitopes to Both CD4 + and CD8 + Diabetogenic T Cells for Tolerance

CTLA‐4Ig blocks the development and progression of citrullinated fibrinogen–induced arthritis in DR4‐transgenic mice

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