Reciprocal relationship of peptide-solid support binding and antibody-peptide binding. Our data indicate that when the peptide binds to the plate tightly, with a low Kp, the antibodies bind the peptide more loosely, with high Kd. And, vice versa, if the peptide is bound loosely, then the antibody-peptide bond will be stronger. This figure represents schematically a possible mechanism for this phenomenon. Panel A: The peptide binds with low affinity, represented here with a single attachment point to the solid support. As a result the antibody has facilitated access to the peptide and the peptide -antibody bond is strong. Panel B: The peptide binds tightly, represented here as multiple attachment points. In this case the access of the antibodies is hindered by steric interference and the antibody-peptide bond is weaker. It is worth noting that our results indicate that by changing the concentration of the peptide at the time of plating it is possible to manipulate the strength of the attachment: High concentration of the peptide result in low affinity binding while low concentrations of the peptide result in high affinity binding.