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Neisseria gonorrhoeae employs two protein inhibitors to evade killing by human lysozyme

Fig 2

Ng_1063 inhibits human lysozyme killing activities in vitro.

A. M. luteus was exposed to vehicle control, 2 μg/mL human lysozyme alone, or 2 μg/mL human lysozyme with increasing concentrations of recombinant 1063 protein (r1063 concentrations indicated in parentheses). Loss of absorbance at λ595 nm, indicating bacterial lysis, was measured over time. n = 3 biological replicates. Differences between vehicle control and lysozyme with 2 μg/mL r1063 were not significant at any time point. B. MS11 WT and ΔltgAΔltgD Gc were exposed to 1.5 μg/mL human lysozyme (HL), which had been left untreated or pretreated with r1063 (0.75 μg/mL final in assay) or recombinant MIP (rMIP, 0.75 μg/mL final in assay), for 5hr. Percent Gc survival was determined by dividing the CFU/mL at 5 hr by the CFU/mL at 0 hr and normalized to the vehicle control (100%). n = 6–15 biological replicates. C. WT, ΔltgAΔltgD, and ΔltgAΔltgD::1063+ complement Gc were exposed to 10 μg/mL human lysozyme (HL) for 3 hr. Gc survival was determined as in Fig. 2B. NS, not significant. n = 3–6 biological replicates. All values are represented as the mean ± SEM. *p < 0.05; two tailed t-test.

Fig 2