Antigens, Plant/adverse effects; Celiac Disease/immunology; Flour/adverse effects; Gliadin/adverse effects; Intestinal Mucosa/immunology; Triticum/adverse effects; Adolescent; Adult; Antigens, Plant/analysis; Antigens, Plant/metabolism; Celiac Disease/diet therapy; Celiac Disease/metabolism; Celiac Disease/pathology; Cell Proliferation; Cells, Cultured; Child; Child, Preschool; Clone Cells; Diploidy; Flour/analysis; Gliadin/analysis; Gliadin/metabolism; Humans; Interferon-gamma Release Tests; Intestinal Mucosa/metabolism; Intestinal Mucosa/pathology; Intestine, Small/immunology; Intestine, Small/metabolism; Intestine, Small/pathology; Lymphocyte Activation; Middle Aged; Protein Hydrolysates/adverse effects; Protein Hydrolysates/analysis; Protein Hydrolysates/metabolism; Species Specificity; T-Lymphocytes/immunology; T-Lymphocytes/metabolism; T-Lymphocytes/pathology; Tissue Culture Techniques; Triticum/chemistry; Triticum/genetics; Young Adult