Figure 6.
IgM cleavage activity by rIdeSsuis leads to reduction of C3 antigen on the bacterial surface. S. suis strain 10 (wt), 10∆ideSsuis (∆ideSsuis), 10∆ideSsuis∇ideSsuis_EcoRI (∇ideSsuis_EcoRI), 10∆ideSsuis∇ideSsuis_C195S (∇ideSsuis_C195S) were incubated in a 1:2 diluted IgG depleted porcine anti-S. suis serotype 2 hyperimmune serum. After incubation at 37°C, bacteria were stained with a FITC-labeled rabbit anti-human C3c antibody and measured by flow cytometry. S. suis strain 10 incubated in undiluted serum served as positive control (+ ctrl). S. suis strain 10 incubated with heat-inactivated serum served as negative control (- ctrl). Bars and error bars represent mean and standard deviation. Significant differences are indicated by asterisks. Probabilities were considered as follows p < 0.05 *, p < 0.01 **, p < 0.001 ***.