Ag-specific interactions between CD4⁺ T cells and DCs induce podosome dissolution in DC. (A) Untreated or PTX-treated DCs were cocultured with CD4⁺T cells on coverslips in the presence or absence of TSST1. Cells were then fixed and labeled with antivinculin Ab (green) and phalloidin (red). Bar, 10 μm. (B) DC-presenting podosomes were quantified, plotted to the total number of cells present in the field, and presented as percentages. Means plus or minus SD of 4 independent experiments are shown; at least 25 total cells were examined for each condition in each experiment. Significance was assessed by Student unpaired t test (*P < .05; **P < .005).