Figure 1.

Anti-CTLA-4 and anti-PD-1 therapeutic antibodies have differential FcγR-binding requirement for optimal activity. In the mechanisms of action of anti-CTLA-4 antibodies (A), depletion of Tregs after engaging FcγR⁺ effector cells [macrophages (Mϕ) and NK cells] plays a critical role in their efficacy. In contrast, anti-PD-1 antibodies need to have the Fc-mediated effector functions (ADCC, ADCP, and CDC) removed to avoid the killing of PD-1⁺ T cells by FcγR⁺ effector cells (B).