Pharmacologic glycoengineering of Fcγ receptor IIIa enhances force-resistant IgG-FcγR interactions and anti-tumor antibody efficacy.

Therapeutic monoclonal antibodies (mAbs) are central to cancer treatment but often show incomplete efficacy. We show that transient pharmacologic inhibition of complex N-glycans in host cells ("glycoengineering") enhances the in vivo activity of multiple depleting mAbs, including mAbs already engineered for heightened potency. In preclinical models, glycoengineering improved α-CD20-mediated tumor clearance and survival through FcγRIIIa- and natural killer (NK) cell-dependent pathways. In B16-F10 melanoma, glycoengineering similarly enhanced anti-CD25 depletion of intratumoral regulatory T cells (Tregs). Notably, glycoengineering produced minimal changes in equilibrium binding affinity but markedly increased the mechanical durability of IgG-FcγRIIIa interactions under physiological shear stress. These results establish antibody effector function as a mechano-immunological process in which IgG-FcγR interactions can be tuned for resilience to physiological forces, thereby moving beyond the current affinity-centric paradigm in mAb engineering. Integrating mechanobiology into therapeutic development may enable mAbs optimized for the dynamic forces of human physiology, which provides a route to enhance next-generation immunotherapies.