Proposed model for how antibody binding affinity to target antigen regulates effector function potency.

Enhanced intrinsic affinity increases the likelihood for bivalent interaction with target cell. In contrast, a reduction in intrinsic affinity improves the probability for monovalent binding, leading to increased amount of antibody-Fc domains interacting with the target cell and hence better engagement with effector elements. However, additional reduction in intrinsic affinity, beyond a threshold of minimum affinity will result in poor cellular interaction and reduced effector functions.