Figure 1.

Antibody-dependent cellular cytotoxicity in therapeutic antibody treatment. (A) Without antibody therapy, NK cells are tolerant to healthy cells and tumor cells, if the strength of activating signal they receive upon encountering activating ligands on these malignant cells does not overcome the inhibitory signaling delivered by inhibitory ligands as, e.g., MHC class I molecules. (B) Upon treatment with tumor antigen-associated (TAA) specifc antibody, the activating stimulus from FcγRIIIa induced by antibodies cross-linking NK cells with TAA-expressing healthy and malignant cells overcomes inhibitory signals. This leads to the activation of NK cells and ADCC is mediated by releasing cytotoxic granules containing perforin and granzyme.