Purified PMNs express FcγRIIIA protein. (A) Purified PMNs from FcγRIIIB WT donors and the FcγRIIIB-null individual were stained with FITC-labeled (clones MEM154 and 3G8; both mIgG1) or unlabeled (clones CBL-Gran/11 and GRM1; both mIgG2a) anti-CD16 antibodies, followed by goat anti-mouse IgG–FITC (thick lines). Appropriate negative controls were used in each case (thin lines). (B) Purified MNCs, PMNs, or monocytes (Mono) isolated from 2 FcγRIIIB WT donors and the null individual were lysed and western blot analysis was performed using antibodies recognizing FcγRIIIA and FcγRIIIB (left panel) or specific for FcγRIIIA only (right panel). Actin antibody was used as control. The indicated bands for FcγRIIIB, FcγRIIIA, and actin were 50-75 kDa, 70 kDa, and 45 kDa, respectively.³³  The results are representative of at least 3 experiments.