Fig 4.

Tc proteins do not inhibit killing of intracellular Y. pestis by PMNs. Y. pestis KIM6+(pCD1Δ1234) (open circles) or KIM6+ ΔyitA-yipB(pCD1Δ1234) (solid circles) recovered from infected fleas was used to infect PMNs. After 45 min, gentamicin was added to eliminate remaining extracellular bacteria. Medium containing gentamicin was then removed, and fresh medium without gentamicin was added (T0 sample). Additional samples were collected after 60 and 180 min of incubation, and the number of recovered CFU was compared to that of the T0 sample. The means and standard errors for at least three experiments are indicated. Data were analyzed by paired Student's t test. No significant differences between the strains were observed.