EPITOPE FINGERPRINTING USING OVERLAPPING 20-MER PEPTIDES OF THE MUC1 TANDEM REPEAT SEQUENCE

The ISOBM TD-4 Workshop antibodies 122-177 were tested for reactivity with 20 overlapping MUC1 tandem repeat 20-mer peptides by an ELISA, in order to determine the complete amino acid sequences of the epitopes, Of the 56 antibodies studied, 30 showed specific binding and thus the epitopes were characterized. The epitopes appear to be 'broader' when compared to those deduced from studies using smaller peptides. Intera ssay variation is remarkably small, allowing for precise grouping of c lusters with very similar epitope patterns, Five groups of antibodies show remarkable similarity: BC3 and VU-4-H5; BC4W154, C595 and Mc5; MF 06 and B27.29; VU-11-D1 and VU-11-E2; Ma552, VU-3-C6, 7540MR and BC4E5 49. We have used the term 'epitope fingerprinting' to refer to the 'fi ne structure' of the epitope with all its essential and flanking amino acids, We believe this method is more precise than the usual epitope mapping with short peptides.