Nonfucosylated anti-CD20 antibody potentially induces apoptosis in lymphoma cells through enhanced interaction with FcγRIIIb on neutrophils

We demonstrate herein the augmentation of rituximab-mediated apoptosis in lymphoma cell lines by cross-linking with recombinant Fc gamma Rs, which is further enhanced by using a nonfucosylated variant of rituximab having strong Fc gamma RIII-binding capacity. Furthermore, we show that neutrophils can serve as physiological cross-linkers that augment anti-CD20-mediated apoptosis, as evidenced by (i) the neutrophil-augmented apoptosis was more profound for the nonfucosylated variant of rituximab and (ii) the mechanism depended on Fc gamma RIIIb but not on Fc gamma RIIa. Taken together, we suggest a potential antitumour mechanism of nonfucosylated anti-CD20 antibody by which antibody molecules are cross-linked through enhanced interaction with Fc gamma RIIIb in neutrophils. (C) 2009 Elsevier Ltd. All rights reserved.