FIG. 6.
Phagocytosis of wild-type and hya mutant Salmonella serovar Typhimurium by RAW 264.7 murine macrophages. Macrophages (1 × 105) were infected with 1 × 108 FITC-conjugated live wild-type (wt) or hya cells or beads or with 5 × 106 FITC-conjugated killed E. coli cells. Macrophages were examined 1.5 h later for adherence or phagocytosis by fluorescence quenching, using a Leica TCS inverted epifluorescence microscope. The number of macrophages containing one or more bacterial cells or beads per 100 to 200 macrophages was counted and expressed as percent internalization. The results are averages for three trials.