FIG 7.

Growth and cytotoxicity of the virB6-4::Himar1 mutant. The growth of A. phagocytophilum virB6-4::Himar1 (dotted line) versus wild-type (wt) (black line) in infected HL-60 (A) and ISE6 (B) cells was followed by determining the number of A. phagocytophilum genome equivalents per host cell targeting the A. phagocytophilum single-copy gene msp5 and the tlr9 or crt genes from HL-60 and ISE6 cells, respectively. Bars indicate A. phagocytophilum virB6-4::Himar1 and wild-type cytotoxicity to host cells as indicated by the levels of LDH release into the cell culture supernatants. The culture medium was not changed at any time during the course of this experiment. *, P = 0.01 to 0.05; **, P = 0.001 to 0.01. Data were obtained from three independent experiments with three technical replicates.