Table 2.
Anti-fHbp MAb bactericidal activity measured with fH-depleted human complement
| MAb | Bactericidal activity (BC50, μg/ml)a with: |
|||
|---|---|---|---|---|
| fH-depleted complement |
fH-replete complement |
|||
| Mean | Range | Mean | Range | |
| Human IgG1 chimeric mouse anti-fHbp | ||||
| JAR 3 | 1.4 | 0.8–2.0 | 15.2 | 12.5–18 |
| JAR 5 | 1.25 | 1.0–1.5 | 23.5 | 22–25 |
| MAb502 | 1.25 | 0.75–1.5 | >100 | >100 |
| Positive-control mouse IgG2a | ||||
| Anti-PorA P1.7 | 0.5 | 0.3–0.7 | 1.05 | 1.0–1.1 |
| Anticapsular, SEAM 12 | 0.18 | 0.15–0.2 | 1.15 | 1.0–1.2 |
a
Data are means and respective ranges, for values observed in two independent assays, of MAb concentrations that gave 50% killing (BC50) after 1 h of incubation with bacteria and 20% fH-depleted pooled human serum as a complement source that also had been depleted of IgG (see Materials and Methods). Without added MAb, there was >150% survival of the bacteria with fH-depleted or -replete complement. For preparation of fH-replete complement, 50 μg/ml of human fH was added.