Antibody on and off rates are capped by the affinity maturation process

Summary

Antibody on and off rates are capped by the affinity maturation process (1). Authors propose caps of $10^5$ to $10^6{M}^{-1}{s}^{-1}$ for $k_{on}$ and $10^{-3}$ to $10^{-4}{s}^{-1}$ for $k_{off}$, leading to a cap of $10^{-10}M$ for $k_d$, beyond which B cells would have no selective advantage. The on-rate cap is due to diffusion limits, while the off-rate is governed by antibody reabsorption and endocytosis.

1.

Foote J, Eisen HN. Kinetic and affinity limits on antibodies produced during immune responses. Proceedings of the National Academy of Sciences. 1995;92(5):1254–6. Available from: https://doi.org/10.1073/pnas.92.5.1254