Fig. 3.

Inhibition of fH binding by anti-fHbp MAbs. (A) ELISA. Inhibition of binding of fH (2 μg/ml) to recombinant fHbp immobilized on a microtiter plate is shown. ▿, JAR 3; ×, JAR 5; ○, MAb502. Error bars represent the OD range for two independent experiments. (B and C) Flow cytometry. (B) Inhibition of binding of fH (∼90 μg/ml in 20% IgG-depleted human serum) to live bacterial cells by 50 μg/ml of MAb. Black solid line, MAb502; dotted black line, JAR 3; gray solid line, JAR 5; dark gray filled area, bacteria without fH or MAb as a negative control; light gray filled area, bacteria with fH without a MAb as a positive control. (C) Same conditions as for panel B except that 2 μg/ml of each of the anti-fHbp MAbs was tested instead of 50 μg/ml. The ELISA and flow cytometry data were replicated in at least two independent experiments.