Characterization of NK-cell RTX-binding and RTX-mediated ADCC activity by NK cells against Daudi and ARH-77 CD20⁺ B cells. RTX-mediated ADCC activity by NK cells against (A) ARH-77 and (B) Daudi CD20⁺ B cells was assayed for 9 donors whose genotyping demonstrated FcγRIIIa-158 V/V (n = 3), V/F (n = 3), and F/F (n = 3) and (C) NK-cell RTX binding. (D) The correlation between cell-surface CD16 receptors and RTX-dependent ADCC activity for these individuals. Values represent means plus or minus SE.