FIG. 2.

F. tularensis LVS LPS did not antagonize PMN priming by a potent endotoxin. Conditions are as described for Fig. 1 except that F. tularensis (Ft) LVS LPS, msbB LOS, or buffer was added to PMN 5 minutes before N. meningitidis (Nm) LOS was added. Cells were then incubated at 37°C for 30 min, and lucigenin and f-Met-Leu-Phe were injected at time zero. The results from one experiment are presented in two panels for clarity. A, Penta-acylated LOS from an msbB mutant antagonized priming by 5 ng/ml of N. meningitidis LOS at 10- and 100-fold excesses (P < 0.05 for each concentration of msbB LOS in comparison with N. meningitidis LOS at 5 ng/ml). B, F. tularensis LVS LPS had no significant effect on priming by N. meningitidis LOS at the same excess concentrations (P > 0.05 for the comparison between each concentration of F. tularensis LVS LPS and N. meningitidis LOS). Results are the averages for duplicate samples ± standard errors of the means and are representative of those from three experiments. ALU, arbitrary light units.