Epitope fingerprints reveal the amino acids essential for binding and, when required for binding, additional structural constraints. The information is obtained from a single experiment and it truly represents an antibody’s individual epitope fingerprint. Ideally the entire procedure takes only 2-3 weeks and requires minimal amounts of antibody, in the case of IgG even with unpurified protein samples.
Since all peptides selected are expressed on phage, identified disulfide bridges will fold properly even as a synthetic peptide, but they are still difficult to predict in synthetic peptides.
Even for unknown antigens the epitope can be identified, if a sufficiently large number of amino acid residues is enriched, that allows identification by protein data-base searches.
Otherwise, an epitope is often approached by describing roughly the region or sequence in the antigen recognized by an antibody. This requires much more time and materials for peptide screening, alanine scanning, structural optimization, and positional screens for alternative amino acids.
Epitope fingerprint of Dupilumab as identified by epitope fingerprinting. The alignment shows only sequences with 5 consecutive identical amino acids out of a pool of more than 2,000 sequences with at least 4 amino acids identity. Strongest enrichment: Cys-flanked constrained peptide (red frame). Click on this link or the graphic to obtain a longer list of similar sequences.