Isolation of peptides useful for differential diagnosis of Crohn's disease and ulcerative colitis.

Abstract

Phage displayed random peptide technology has been utilised to identify binding epitopes of antibodies or receptor ligands. To isolates peptides from a phage library which are specifically recognised by antibodies in serum from patients with Crohn's disease (CD). A phage displayed random peptide library composed of nine amino acids was established and sequentially screened using serum immunogloblin G obtained from CD patients. Five different CD specific peptides were isolated from the phage library. No homology in amino acid sequences was observed among four (CDP-1, -3 to -5) of the five peptides exhibiting different binding characteristics with each CD patient's serum. In contrast, two peptides (CDP-1 and -2) had similar amino acid sequences and similar binding characteristics. Four multiple antigenic peptides (MAP, CDP-1, -3 to -5) were synthesised, and an enzyme linked immunosorbent assay (ELISA) using the four peptides was developed to detect serum antibodies against them. Fifty two of 92 CD patients (56.5%) were detected by ELISA, none of 20 ulcerative colitis (UC) patients, only one of 25 duodenal ulcer patients, and only three of 48 healthy subjects. ELISA using the four peptides isolated in this study may be useful for the differential diagnosis of CD and UC.