Dose-response curves and contact-dependent activation of PMNs. (A-B) Purified PMNs from FcγRIIIB WT donors and the null individual were stimulated for 4 hours with CLL B cells opsonized with increasing concentrations of RTX-GE. CD11b (A) and CD62L (B) expression on PMNs was analyzed by flow cytometry. (C) FcγRIIIB WT PMNs were activated with CLL B cells opsonized with RTX, RTX-GE, or CTX (CTRL), either together in standard 24-well plates or separated from each other in Transwells. The data are the means and standard deviations of 3 or 4 experiments. *P < .05 vs control (CTRL).