title: Selective inhibition of the gliadin-specific, cell-mediated immune response by transamidation with microbial transglutaminase.
abstract: CD is an immune-mediated enteropathy caused by the ingestion of wheat gluten. The modification of gluten by intestinal tTGase plays a crucial role in CD pathogenesis. In this study, we observed that extensive transamidation of wheat flour with K-C2H5 by mTGase yielded spf and K-gliadins fractions. By Western blot, we found that these modifications were associated with strongly reduced immune cross-reactivity. With the use of DQ8 tg mice as a model of gluten sensitivity, we observed a dramatic reduction in IFNγ production in gliadin-specific spleen cells challenged with spf and K-gliadins in vitro (n=12; median values: 813 vs. 29 and 99; control vs. spf and K-gliadins, P=0.012 for spf, and P=0.003 for K-gliadins). For spf, we also observed an increase in the IL-10/IFNγ protein ratio (n=12; median values: 0.3 vs. 4.7; control vs. spf, P=0.005). In intestinal biopsies from CD patients challenged in vitro with gliadins (n=10), we demonstrated further that K-gliadins dramatically reduced the levels of antigen-specific IFNγ mRNA in all specimens responsive to native gliadins (four of 10; P<0.05). As cytotoxic effects have been described for gliadins, we also studied GST and caspase-3 activities using the enterocytic Caco-2 cell line. We found that neither activities were modified by flour transamidation. Our results indicate that K-C2H5 cross-linking via mTGase specifically affects gliadin immunogenicity, reversing the inducible inflammatory response in models of gluten sensitivity without affecting other aspects of the biological activity of gliadins.
authors.affiliation: NRC, via Roma 64, Avellino, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Lombardi
authors.forename: Paolo
authors.initials: P
authors.lastname: Bergamo
authors.forename: Francesco
authors.initials: F
authors.lastname: Maurano
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Bozzella
authors.forename: Diomira
authors.initials: D
authors.lastname: Luongo
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mazzarella
authors.forename: Vera
authors.initials: V
authors.lastname: Rotondi Aufiero
authors.forename: Gaetano
authors.initials: G
authors.lastname: Iaquinto
authors.forename: Mauro
authors.initials: M
authors.lastname: Rossi
mesh_terms: D000293:Adolescent; D000328:Adult; D001706:Biopsy; D018938:Caco-2 Cells; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D002446:Celiac Disease / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D002648:Child; D005260:Female; D005433:Flour; D015870:Gene Expression / Q000187:drug effects; D005903:Gliadin / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects*; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D016753:Interleukin-10 / Q000096:biosynthesis / Q000276:immunology; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D020033:Protein Isoforms / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D011503:Transglutaminases / Q000378:metabolism*
chemical_list: C556062:IL10 protein, mouse; D020033:Protein Isoforms; D012333:RNA, Messenger; D016753:Interleukin-10; D007371:Interferon-gamma; D005903:Gliadin; D011503:Transglutaminases; D005982:Glutathione Transferase; C505409:Casp3 protein, mouse; D053148:Caspase 3