HIGK cells were transfected with exogenous cofilin, constitutively active cofilin (S3A), or constitutively inactive cofilin (S3E). Control was transfection agent only. A) Confirmation of an increase in cofilin expression in transfected cells. Cofilin-transfected HIGK cells (or control) were labeled with cofilin antibodies (yellow) and analyzed by CSLM. Magnification x63. B) Fluorescence intensity analysis of cofilin HIGK cells. Intensity values were obtained using Leica Confocal software (arbitrary units) to calculate cofilin fluorescence intensity. Results are representative of two independent experiments (n=3 coverslips/group). Data are means and error bars indicate standard deviations. *, P <0.05; **, P <0.01; ***, P <0.001 by unpaired t-test to control. C) Cofilin-transfected cells were infected with P. gingivalis for 10 min and analyzed by CSLM. P. gingivalis (green) was detected with specific antibodies, actin (red) was stained with TRITC-phalloidin, and nuclei (blue) stained with DAPI. Magnification x63. Results are representative of three independent assays. Data shown are maximum projections of z-stacks (10 slices/z stack, 3 coverslips/group). D) Invasion levels of P. gingivalis following cofilin-transfection. Numbers of intracellular bacteria were counted throughout z-stacks (10 slices/stack; 3 coverslips/group). Results are representative of three independent assays. Data are ratios of internalization in transfected-infected groups compared with non-transfected control-infected cells. *, P <0.05; **, P <0.01 by unpaired t-test to control.