Antibody Repertoire Profiling Using Bacterial Display Identifies Reactivity Signatures of Celiac Disease

• Published in: Analytical chemistry (Washington) Vol. 85; no. 2; pp. 1215 - 1222
• Main Authors: Spatola, Bradley N, Murray, Joseph A, Kagnoff, Martin, Kaukinen, Katri, Daugherty, Patrick S
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 15.01.2013
• Subjects: Adult; antibodies; Antibodies - analysis; Antibodies - immunology; antibody specificity; Antigen-Antibody Reactions; Antigens; Autoimmune diseases; Bacteria; blood serum; Celiac disease; Celiac Disease - diagnosis; Celiac Disease - immunology; Cell Surface Display Techniques; Escherichia coli - chemistry; Escherichia coli - immunology; Female; Flow Cytometry; fluorescent dyes; gliadin; Humans; Male; Middle Aged; patients; peptide libraries; Peptide Library; Peptides; Peptides - chemistry; Peptides - immunology; protein-glutamine gamma-glutamyltransferase; Reagents; Sensitivity and Specificity; Tissues
• ISSN: 0003-2700; 1520-6882; 1520-6882
• DOI: 10.1021/ac303201d

A general strategy to identify serum antibody specificities associated with a given disease state and peptide reagents for their detection was developed using bacterial display peptide libraries and multiparameter flow cytometry (MPFC). Using sera from patients with celiac disease (CD) (n = 45) or healthy subjects (n = 40), bacterial display libraries were screened for peptides that react specifically with antibodies from CD patients and not with those from healthy patients. The libraries were screened for peptides that simultaneously cross-react with CD patient antibodies present in two separate patient groups labeled with spectrally distinct fluorophores but do not react with unlabeled non-CD antibodies, thus affording a quantitative separation. A panel of six unique peptide sequences yielded 85% sensitivity and 91% specificity (AUC = 0.91) on a set of 60 samples not used for discovery, using leave-one-out cross-validation. Individual peptides were dissimilar with known CD-specific antigens tissue transglutaminase (tTG) and deamidated gliadin, and the classifier accuracy was independent of anti-tTG antibody titer. These results demonstrate that bacterial display/MPFC provides a highly effective tool for the unbiased discovery of disease-associated antibody specificities and peptide reagents for their detection that may have broad utility for diagnostic development.