MOLECULAR MIMICRY AS A POSSIBLE CAUSE OF AUTOIMMUNE REACTIONS IN CELIAC-DISEASE - ANTIBODIES TO GLIADIN CROSS-REACT WITH EPITOPES ON ENTEROCYTES

Structural similarities between external antigen and self components a re believed to be one of the possible causes of autoimmunity. This stu dy describes the presence of similar structures shared by gliadin and enterocyte surface molecules recognized by antigliadin mAbs. The react ivity of mAbs to gliadin was followed by ELISA using fixed enterocytes , their brush-border membranes, or purified enterocyte antigen. The sp ecificity of reaction was confirmed by ELISA inhibition studies and by immunohistochemical staining of rat tissue sections using biotin-avid in-peroxidase technique. Immunoprecipitation analysis of I-125-labeled intestinal epithelial cells using antigliadin mAb revealed the presen ce of two main cross-reactive molecules of 28 and 62 kDa. The 62-kDa a nd an associated 66-kDa protein were isolated by affinity chromatograp hy. Immunoblotting analysis showed that a 28-kDa protein detected by i mmunoprecipitation also reacted with IgA of celiac disease patient ser a. (C) 1995 Academic Press, Inc.