Dataset Information

Immunoglobulin V-gene usage among human serum IgA with or without specificity to the autoantigen transglutaminase 2

ABSTRACT: To study V-gene usage among antigen-specific and non-antigen-specific serum IgA antibodies in celiac disease patients, purified antibody fractions were subjected to proteomic analysis. Patients either had eastablished, untreated disease with severe intestinal inflammation or "potential" celiac disease characterized by presence of antibodies but no or mild inflammation. Quantification of the fraction of antibodies using different IGHV segments revealed that antibodies specific to the autoantigen transglutaminase 2 (TG2) displayed a bias toward usage of IGHV5-51 in agreement with previous observations. The fraction of antibodies using IGHV5-51 correlated with the degree of intestinal inflammation, indicating that production of hallmark IGHV5-51 anti-TG2 antibodies coincides with onset of clinical celiac disease.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Blood Serum

DISEASE(S): Celiac Disease

SUBMITTER: Rasmus Iversen

LAB HEAD: Ludvig M. Sollid

PROVIDER: PXD013777 | Pride | 2019-07-09

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	1452_1477_1491_1565.zip	Other
	1497_1502_1508_1524.zip	Other
	1520_1424_1581_1291.zip	Other
	CD1291_Marsh0_Anti-TG2_1.raw	Raw
	CD1291_Marsh0_Anti-TG2_2.raw	Raw

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Publications

Efficient T cell-B cell collaboration guides autoantibody epitope bias and onset of celiac disease.

Iversen Rasmus R Roy Bishnudeo B Stamnaes Jorunn J Høydahl Lene S LS Hnida Kathrin K Neumann Ralf S RS Korponay-Szabó Ilma R IR Lundin Knut E A KEA Sollid Ludvig M LM

Proceedings of the National Academy of Sciences of the United States of America 20190708 30

B cells play important roles in autoimmune diseases through autoantibody production, cytokine secretion, or antigen presentation to T cells. In most cases, the contribution of B cells as antigen-presenting cells is not well understood. We have studied the autoantibody response against the enzyme transglutaminase 2 (TG2) in celiac disease patients by generating recombinant antibodies from single gut plasma cells reactive with discrete antigen domains and by undertaking proteomic analysis of anti- ...[more]

PMID: 31285344

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Project description:Celiac disease (CD) is a chronic inflammation of the small intestine triggered by the ingestion of gluten in genetically predisposed individuals. Tissue transglutaminase (TG2) is a key factor in the pathogenesis of CD, because it catalyzes both the deamidation of specific glutamine residues and the formation of covalent Nε-(γ-glutamyl)-lysine isopeptide crosslinks resulting in TG2-gluten peptide complexes. These complexes are thought to activate B cells causing the secretion of anti-TG2 autoantibodies that serve as diagnostic markers for CD, although their pathogenic role remains unclear. To gain more insight into the molecular structures of TG2-gluten peptide complexes, we developed a reciprocal proteomic analysis strategy, which facilitates the comprehensive identification of isopeptides in a complex protein hydrolysate. The workflow consists of four steps: (1) performance of the model reaction between TG2 and gluten peptide(s) followed by tryptic hydrolysis, clean-up and untargeted nLC-MS/MS analysis (2), prediction of tryptic TG2-derived lysine peptides that serve as potential isopeptide modifications (3) the search for isopeptides by configuring the TG2-modifications in MaxQuant and search against the α-gliadin fasta file and (4) the reciprocal search for isopeptides by configuring the gluten peptide(s) as modification in MaxQuant and search against the TG2 fasta file. After verification by manual data curation and visualization, this strategy enabled the identification of 26 different isopeptides involving 19 TG2 lysine residues, only six of which were known previously. Experiments with different TG2-gluten peptide molar ratios revealed that K-425, K-590, K-600 and K-649 were the most preferred lysine residues involved in isopeptide crosslinking. Further, expanding the model system to three gluten peptides allowed the localization of the preferred glutamine crosslinking sites. The described strategy is generally applicable to any hydrolysate containing isopeptides and these new insights into the structure of TG2-gluten peptide complexes may help clarify the role of extracellular TG2 in CD autoimmunity and in other inflammatory diseases.