Epitopes Related to Coeliac Disease

Abstract

The invention herein disclosed is related to epitopes useful in methods of diagnosing, treating, and preventing coeliac disease. Therapeutic compositions which comprise at least one epitope are provided.

Description

[0001]The invention relates to epitopes useful in the diagnosis and therapy of coeliac disease, including diagnostics, therapeutics, kits, and methods of using the foregoing.[0002]Coeliac disease is caused by an immune mediated hypersensitivity to dietary gluten. Gluten proteins in wheat, rye, barley and in some cases oats are toxic in coeliac disease. Gluten is composed of alpha / beta, gamma and omega gliadins, and low and high molecular weight (LMW and HMW) glutenins in wheat, hordeins in barley, secalins in rye and avenins in oats. Hordeins and secalins are homologous to gamma and omega gliadins and low and high molecular weight glutenins in wheat. Avenins are phylogenetically more distant than hordeins and secalins from wheat gluten.[0003]The goal of research in coeliac disease has been to define the toxic components of gluten by defining the peptides that stimulate gluten-specific T-cells. Precise definition of gluten epitopes permits development of new diagnostics, therapeutics...

AI Technical Summary

Benefits of technology

[0006]Modification of gluten by the enzyme, tissue transglutaminase (tTG) present in intestinal tissue, substantially increases gluten's stimulatory capacity on gluten specific T-cells. Most of the known epitopes for gluten-specific T-cells correspond to tTG-deamidated gluten peptides. Transglutaminase mediates deamidation of specific glutamine residues (to glutamate) in gluten. Glutamine-containing sequences susceptible to deamidation by tTG generally conform to a motif: QXPX or QXX (FYMILVW) (see Vader W. et al 2002 J. Exp. Med. 195:643-649, PCT WO 03 / 066079, and Fleckenstein B. 2002. J Biol Chem 277:34109-16). The motif for peptides that bind to HLA-DQ2 and that are susceptible to deamidation by tTG has been used to predict certain gluten epitopes (Vader et al J Exp Med 2002 J. Exp. Med. 195:643-649, PCT WO 03 / 066079).

[0008]Our work has exploited the observation that gluten challenge in vivo induces HLA-DQ2 restricted CD4+ gluten-specific T-cells in peripheral blood expressing a gut-homing integrin (alpha4beta7). This technique allowed the mapping of the dominant epitope in A-gliadin (57-73 QE65) (Anderson, R P et al 2000. Nat. Med. 6:337-342, WO 01 / 25793). A-gliadin 57-73 QE65 corresponds to two overlapping epitopes identified using intestinal T-cell clones (Arentz-Hansen H. et al 2000. J. Exp. Med. 191:603-612, Arentz-Hansen H. et al 2002. Gastroenterology 123:803-809). The advantage of in vivo gluten challenge to induce gluten specific T-cells is that any food can be consumed and the resulting T-cells induced in blood (quantified in peripheral blood using a simple overnight interferon gamma ELISPOT assay) will have been stimulated in vivo by endogenously presented epitopes, rather than primed in vitro by a synthetic or purified antigen. Overnight assays of fresh polyclonal peripheral blood T-cells also avoid the potential for artefacts associated with the lengthy purification of T-cell clones.

Problems solved by technology

Gluten proteins in wheat, rye, barley and in some cases oats are toxic in coeliac disease.

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