An immunodominant DQ8 restricted gliadin peptide activates small intestinal immune response in in vitro cultured mucosa from HLA-DQ8 positive but not HLA-DQ8 negative coeliac patients

• Published in: Gut 2003-01, Vol.52 (1), p.57-62
• Main Authors: Mazzarella, G, Maglio, M, Paparo, F, Nardone, G, Stefanile, R, Greco, L, van de Wal, Y, Kooy, Y, Koning, F, Auricchio, S, Troncone, R
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; alkaline phosphatase/antialkaline phosphatase; APAAP; CD3 Complex; Celiac disease; Celiac Disease - immunology; Cloning; coeliac disease; Epitopes - immunology; Fas; fas Receptor - analysis; Female; Gliadin - immunology; gliadin peptides; Health aspects; HLA class II antigens; HLA restriction; HLA-DQ Antigens - immunology; Humans; ICAM-1; Immunophenotyping; intercellular adhesion molecule 1; Intercellular Adhesion Molecule-1 - analysis; Intestinal Mucosa - immunology; Jejunum; Laboratories; lamina propria mononuclear cells; LPMNC; Lymphocyte Activation; Lymphocytes; Male; Middle Aged; mucosal immunity; organ culture; Organ Culture Techniques; PAP; Patients; PBS; peptic-tryptic digest; Peptides; peroxidase-antiperoxidase; Phosphatase; phosphate buffered saline; Receptors, Interleukin-2; Rodents; Small Intestine; Statistics, Nonparametric; Studies; T-Lymphocytes - immunology; TBS; Tris buffered saline
• ISSN: 0017-5749; 1468-3288; 1458-3288
• DOI: 10.1136/gut.52.1.57

Background: Studies on intestinal T cell clones from the mucosa of patients with coeliac disease have led to the identification of immunogenic gliadin epitopes. One is HLA-DQ8 restricted, its recognition by T cells being increased by introduction of negatively charged residues operated by tissue transglutaminase. Aim: To test HLA-DQ8 restricted epitope in both native (QYPSGQGSFQPSQQNPQA) and deamidated (QYPSGEGSFQPSQENPQA) forms in an organ culture system of treated coeliac mucosa from HLA-DQ8 positive and HLA-DQ8 negative patients. Patients and methods: Jejunal biopsies obtained from 10 patients with coeliac disease (six HLA-DQ8 positive and four HLA-DQ8 negative) were cultured in vitro with a peptic-tryptic digest (PT) of gliadin, or with the native (peptide A) or deamidated (peptide B) peptide. Intraepithelial CD3+ and lamina propria total CD25+ and CD3+CD25+ cells were counted, lamina propria intercellular adhesion molecule 1 (ICAM-1) expression was evaluated, as well as that of Fas molecules on epithelial cells. Results: In HLA-DQ8 positive, but not in HLA-DQ8 negative, coeliacs the density of intraepithelial CD3+ cells, lamina propria total CD25+, and CD3+CD25+ cells, as well as expression of ICAM-1 and Fas molecules were significantly increased in biopsies cultured with PT, peptide A, or peptide B compared with biopsies cultured in medium alone. Conclusion: These data show that the DQ8 restricted gliadin peptide is immunogenic only in the intestinal mucosa of HLA-DQ8 positive coeliac patients in both native and deamidated forms.