Epitope mapping and non-A mutant reactivity. (A) Top blot: Dot-blot hybridization of the T26 mAb onto overlapping 10-amino acid peptides (with an offset of one amino acid) spanning the used immunogen. Lower diagram: Schematic representation of the corresponding peptide sequence and T26 mAb binding. Blue represents the common part of the peptides recognized by the antibody. (B) Non-A mutant reactivity. Top blot shows dot-blot hybridization of the T26 mAb onto 21 13-amino-acid peptides containing the unique sequence of the known non-A NPM1 mutants. (Bottom diagram) Schematic representation of the corresponding peptide sequence and T26 mAb binding. Yellow represents the alanine residue at position +3.