Binding of Gram-positive and Gram-negative bacteria to CD163-expressing CHO cells. FITC-labeled S mutans, S aureus, and E coli were incubated with CD163-expressing CHO cells or cells expressing empty vector (EV) and bacterial binding was assessed by flow cytometry as described in “Cell binding assays.” CD163-CHO cells (open histograms) show clearly increased bacterial binding as compared with CHO EV (filled histograms). The panel at bottom right shows the average mean fluorescence intensities (MFIs) plus or minus standard deviation of 3 independent experiments. Statistics: 2-tailed Student t test.