In vitro presentation of gliadin-derived peptides by different cell lines.

CHIRDO FG,; ZWIRNER NW,; RUMBO M,; CARLOS ALBERTO FOSSATI

CLINICA CHIMICA ACTA

ELSEVIER SCIENCE BV

Año: 2002 vol. 317 p. 151 - 158

0009-8981

Background: Gliadin peptide presentation and T-cell activation are critical events in the pathogenesis of celiac disease.Several studies have been performed to identify the toxic gliadin peptides but the complexity of the antigenic fraction makesthis analysis difficult. In this work, an in vitro model for the analysis of gliadin peptide presentation is studied. Methods:The human cell lines U937 and THP-1 (monocytic), DUCAF and VAVY (immortalised B cells) and HT-29 and Caco-2(intestinal epithelial cells) were incubated with biotin-labelled gliadin (bG). FITC-labelled streptavidin was used to detectbiotinylated peptides at the cell surface by flow cytometry. Results: All cell lines tested showed a fluorescence signal derivedfrom bG, that was highest when cells were stimulated with IFN-g for 48 h. Time course experiments performed using THP-1cells showed that after 4-h incubation, almost a maximal signal can be reached. THP-1 cells incubated at 4 C or afterparaformaldehyde fixation showed a substantial signal reduction, suggesting that metabolic activity was necessary for thedetection of the maximal fluorescence signal at the cell surface. The presence of HLA class II-bound biotinylated peptides wasobserved in cell lysates of THP-1 cells incubated with bG. Conclusions: In all cell lines tested, a specific biotin?peptide-derivedsignal was observed. This was increased after IFN-g treatment and decreased after fixation or incubation at low temperature.The signal was higher in monocytic and B-cell lines than in the epithelial cell lines. The use of this procedure could be a usefultool to study the in vitro processing and presentation of naturally gliadin-derived peptides. D 2002 Elsevier Science B.V. Allrights reserved.