OBI-IgA2 is more effective than RTX-IgA2 at triggering ADCC by PMNs. (A) Cell lines representing different B-cell lymphoma entities (Daudi (Burkitt lymphoma); Oci-Ly7, CARNAVAL, and Oci-Ly18 (DLBCL); GRANTA-519 and MINO (mantle cell lymphoma); MEC-2 (CLL)) served as target cells in [51Cr] release assays. (B) ADCC was investigated in [⁵¹Cr] release assays against freshly isolated tumor cells from patients with Waldenström disease (left panel) or CLL (right panel). PMNs served as effector cells at an E:T ratio of 80:1; antibody concentrations were 10 µg/mL. Results are mean ± SEM from ≥2 experiments with effector cells from different donors. *Significant difference specific antibody vs isotype control. ^§Significant difference RTX-IgA2 vs OBI-lgA2. ^#Significant difference lgG1 vs lgA2. Significant differences (P < .05) were calculated using ANOVA. ctrl., control; n.s., not significant; OBI, OBI-IgA2.