FIG 4.

Effect of the addition of a nonbactericidal anti-NspA MAb on serum anti-FHbp bactericidal activity. The anti-NspA MAb (AL12) was tested at 5 μg/ml and 20% human complement. All isolates were resistant to anti-NspA bactericidal activity at MAb concentrations up to 50 μg/ml (the highest concentration tested). The anti-FHbp antisera matched the FHbp amino acid sequence of the test isolates. Ranges represent results from duplicate measurements. Representative results are shown. The data were replicated in two experiments.