FIG 2 .

CspA inhibits all three complement pathways. CspA (■) or HSA (○) (1 to 100 µg/ml) was added together with NHS (20%) diluted in MgEGTA buffer (alternative pathway) (A) or NHS (1%) diluted in GVB++ buffer (lectin and classical pathways) (B and C) to pathway-specific activators. Following incubation, C5b-9 deposition was recorded using an anti-C5b-9 MAb and HRP-conjugated rabbit anti-mouse pAb. C5b-9 deposition from NHS was set to 100%. (D) CspA inhibits classical pathway-mediated hemolysis of amboceptor-coated sheep erythrocytes. CspA (■), ErpC (△), or HSA (○) (used at 2 to 67 µg/ml) was added to NHS (1%), and then this mixture was combined with amboceptor-coated sheep erythrocytes. The mean values out of three separate experiments are shown, and error bars show SD. **, P ≤ 0.01; ***, P ≤ 0.001.