CD163 supports direct binding of Gram-positive and Gram-negative bacteria. CD163-Fc-coated beads (□) or control ICAM3-Fc–coated beads (■) were incubated with S mutans or with E coli bacteria and binding was assessed by flow cytometry as described in “Fluorescent bead adhesion assay.” Bars represent averages plus or minus SD of 2 (S mutans) or 3 (E coli) independent experiments, respectively. Statistics: 2-tailed Student t test.