Figure 4

Complement killing activity of mAb 2D1 in vitro. The G. parasuis serovar 5 strain (diluted to 10³ CFU/mL with PBS) was incubated with mAb 2D1 (complement-inactivated), positive serum against G. parasuis-5 (prepared by immunizing rabbits and preserved in our laboratory), PBS and mAb ApxIV (mAb against Actinobacillus pleuropneumoniae preserved in our laboratory) at 37 °C for 2 h. The mixtures were evenly streaked onto TSA agar plates. After growth for 24–48 h, colony numbers were measured (one-way ANOVA; Tukey’s post hoc test, ***p < 0.001, **p < 0.01, *p < 0.05, ns indicates no statistically significant difference).