Figure 6.

Slit2 does not inhibit neutrophil killing of the extracellular pathogen S. aureus or increase hepatic bacterial load after infection with the intracellular pathogen L. monocytogenes. (A) Human neutrophils (1.5×10⁶) were incubated with N-mSlit2 or control vehicle at 37°C for 10 minutes, and then, 10% human serum and S. aureus (methicillin-resistant S. aureus strain CMRSA-10/USA300 at 1×10⁶ CFU) were added. Samples were incubated at 37°C with 200 rpm shaking for 90 minutes. The number of viable bacteria in these suspensions was determined by plating. (B) N-mSlit2 or control vehicle was administered intravenously by tail vein injection, and L. monocytogenes (5×10⁴ CFU in 200 µl PBS) was injected intravenously 1 hour later. At the indicated time points, mice were euthanized, the left lobe of liver was homogenized in sterile PBS, and bacterial load was determined from serial dilutions on brain heart infusion-agar plates. Mean values ± SEM from six mice per experimental group. *P<0.05 versus input control. ^†P<0.05 versus polymorphonuclear leukocytes alone.