FIGURE 6.

Eater-Fc binds to E. coli killed by exposure to a cationic AMP. Upper panels, histograms of flow cytometry analysis of binding of 200 μm Eater-Fc (open black curve) or IgG-Fc (green curve) to E. coli when compared with secondary reagent only (gray filled curve) or unstained microbes (open gray curve). Eater-Fc bound to E. coli killed by exposure to 4 μm cecropin A for 10 min at 25 °C but not to E. coli treated with 4 μm control cationic peptide 2K1. Eater-Fc binding to control heat-inactivated E. coli is shown for comparison. Lower panels, dot plots of two-color analysis of the same samples as in the upper row, allowing assessment of Eater binding simultaneously with bacterial viability. The percentage of Eater-Fc binding live or dead bacteria, respectively, is indicated. Experiments were repeated three times with similar results.