Fig. 4

Impact of the K62-Dpo30 on bacterial vulnerability to serum killing and neutrophil killing. A Serum-killing assay was conducted by pre-incubating the strain 2492 with K62-Dpo30 or K64-ORF41 protein for 1 h at 37 °C. Subsequently, the strain was incubated with 75% rabbit serum, heat-inactivated rabbit serum or PBS for 2 h at 37 °C. B Neutrophil killing assay was performed by incubating the strain 2492 with K62-Dpo30, K64-ORF41 or PBS with HL60 cells for 45 min at 37 °C. HL60 cells were pre-mixed with 10% baby rabbit serum or heat-inactivated rabbit serum. The percent survival was determined as the number of surviving bacteria relative to the initial inoculum. Data are presented as the mean ± SEM and represent by the three separate experiments. Two-tailed unpaired Student's t-test was used for statistical analysis. * p < 0.05; ** p < 0.01; *** p < 0.001; ****p < 0.0001