FIG. 1.

The competitive ELISA was used to assess the specificity of monoclonal antibody 1G9-1C2. BSA-DDDDDDD-OH conjugate (50 ng of conjugate/well) was used as the adsorbed antigen, and varying graded concentrations (1.0 to 0.002 mM) of H-DDDDDDD-OH (peptide 1), H-GADDDDD-OH (peptide 2), H-TQDDGGK-OH (peptide 3), H-GGEEK-OH (peptide 4), H-VDDDDK-OH (peptide 5), and H-SGSGSGS-OH (peptide 6) were used as the competitive antigens in the presence of antibody 1G9-1C2 (1.0 μg/ml). Antibody 1G9-1C2 was specific and recognized H-GADDDDD-OH nearly as well as H-DDDDDDD-OH. However, the sequences with internal Asp or Glu residues (e.g., H-VDDDDK-OH, H-TQDDGGK-OH, and H-GGEEK-OH) were not recognized and did not cross-react. H-SGSGSGS-OH was a negative-control peptide.