Table 4.

Analysis of F-actin Polymerization following IgG-coated Bead Binding

COS transfectant		Beads triggering F-actin				Total No. of bound beads		Fold increase in F-actin staining intensity*
		No.		%
FcγRIA		6		1		432		3 ± 1
FcγRIIA		104		45		230		9 ± 4

COS cells were incubated with IgG-coated beads for 15 min at 37°C and were fixed and then stained with FITC-phalloidin to detect actin filaments. The cells were analyzed by confocal microscopy and F-actin staining subjacent to bound beads was analyzed for the presence of F-actin extensions around target beads. A 4-μm area beneath bound beads was also measured for F-actin staining intensity and was compared against background cortical F-actin of the same cell to determine a fold increase value. The data are derived from 35 cells for each condition from two experiments. The increase in F-actin staining intensity observed for FcγRIIA compared to FcγRIA is significant (P = 0.02).  

^* Fold increase value derived only from beads which triggered F-actin accumulation.