FIG 3.

Differential survival of N. gonorrhoeae of different Opa expression states after exposure to primary human neutrophils. Adherent, IL-8-treated neutrophils were synchronously exposed to constitutively expressed, nonvariable (A to C), or phase-variable (D to F) N. gonorrhoeae of the indicated Opa profile. Colors match the receptor-binding profile of each strain as in Fig. 1B. At 30 (A and D), 60 (B and E), and 120 (C and F) min postinfection, neutrophils were lysed and CFU of N. gonorrhoeae were enumerated from the lysates. Results are expressed as the average percentage of CFU at that time point divided by the CFU at the start of the experiment (0 min) ± standard errors for n ≥ 4 biological replicates. Statistical comparisons were by two-way ANOVA with post hoc Tukey multiple-comparison test, with the following pairwise significances: *, P < 0.05; **, P < 0.01; ***, P < 0.005; ****, P < 0.0001. Separate ANOVAs were run to compare the variable strains and the nonvariable strains. Correlations between bacterial survival and association with neutrophils (G) and bacterial survival and phagocytosis by neutrophils (H) were calculated using a linear regression model. The R² and P values are reported on the graphs.