Theory 09/Molecular/Antibodies
Cross-Reactivity Is Epitope Distance
The claim
Antibody cross-reactivity is set by the ratio of epitope similarity to affinity, so a high-affinity antibody discriminates a variant that a low-affinity one cannot.
01Mechanism
Discrimination requires the affinity difference between epitopes to exceed the noise in binding; higher affinity raises the absolute difference.
02Prediction
Cross-reactivity should fall as affinity rises.
03Refutation
Cross-reactivity independent of affinity would remove the ratio.