Fig 6. Gr1⁺ cell subpopulations are necessary for the rapid clearance of the CNF1⁺ strain from the blood.

(A and B) Flow cytometry analysis of peripheral blood isolated from mice intravenously infected with 10⁷ CFUs of E. coli ^CNF1+, E. coli ^CNF1- or PBS (control). Percentages of cells expressing (A) CD45 and CD11b or (B) CD45 and Gr1 are indicated (n = 5). (C) BALB/c mice were injected either with an anti-Gr1 antibody or vehicle, and after 48 h, they were inoculated intravenously with 10⁷ CFUs of E. coli ^HLY+CNF1+ or with 10⁷ CFUs of one of the isogenic mutants, E. coli ^CNF1+, E. coli ^HLY+CNF1-, or E. coli ^CNF1-, prior to the collection of peripheral blood at 3, 6, 24 and 48 h for the measurement of CFUs via the plating of serial dilutions. P-values<0.05 (*) were considered statistically significant.