Rosetting of human IgG-coupled SRBC with neutrophils from donor 17.

Neutrophils from control (closed bar) or donor 17 (hatched bar) were incubated with human IgG subtype-coupled SRBC in the absence or presence of 5 μg/mL Fab fragments of anti-CD16 mAb, CLBFcgran-1, or anti CD32A mAb, IV.3. The rosetting assay was performed as described in “Materials and Methods.” Cells were incubated with IgG-coupled SRBC at 4°C, and the rosettes formed were counted by light microscopy. Experiments were performed in duplicate.