Recombinant deamidated gliadin antigen
The present invention provides a method for determining whether a subject is suffering from celiac disease by contacting a sample of bodily fluid from the subject, with an antigen formed from a hexamer of a gliadin fusion protein immobilized on a solid support. The gliadin fusion protein of the antigen includes a recombinant deamidated gliadin linked to a tag such as Glutathione-S transferase (GST) protein. The antigen is prepared by immobilizing the gliadin fusion protein on the solid support. The antigen can further include tissue Transglutaminase (tTG) cross-linked to the gliadin fusion protein. When tTG is present, the tTG and recombinant deamidated gliadin are mixed together prior to immobilization to the solid phase.
1. An antigen for detecting celiac disease, the antigen comprising: a recombinant deamidated gliadin fusion protein consisting of SEQ ID NO:7 or SEQ ID NO:8; wherein the recombinant deamidated gliadin fusion protein is immobilized on a solid support and is capable of binding to anti-deamidated gliadin antibodies.
2. An antigen for detecting celiac disease prepared by the process comprising:
contacting a solid support with a recombinant deamidated gliadin fusion protein consisting of SEQ ID NO:7 or SEQ ID NO:8 such that the recombinant deamidated gliadin fusion protein is immobilized on the solid support, thereby preparing the antigen for detecting celiac disease.
3. A method for diagnosing celiac disease in a subject, the method comprising: (a) contacting a sample of bodily fluid from the subject with the antigen of claim 1 ; (b) detecting any antibody that has become specifically bound to the antigen; and (c) indicating the presence of celiac disease in the subject when antibody is detected in (b).
4. The method of claim 3 , wherein the sample is a blood sample.
5. The method of claim 3 , wherein the detecting step is performed using an assay selected from the group consisting of ELISA, radioimmunoassay (RIA) and immunofluorescence assay.
6. The method of claim 3 , wherein the antibody specific for the antigen is selected from the group consisting of IgG and IgA.
7. A kit comprising: the antigen of claim 1 and a detection reagent.
8. The kit of claim 7 , wherein the kit further comprises at least one additional member selected from the group consisting of buffers, salts, stabilizers and instructions.