Table 2.

Anti-fHbp MAb bactericidal activity measured with fH-depleted human complement

MAbBactericidal activity (BC50, μg/ml)a with:
fH-depleted complementfH-replete complement
MeanRangeMeanRange
Human IgG1 chimeric mouse anti-fHbp
    JAR 31.40.8–2.015.212.5–18
    JAR 51.251.0–1.523.522–25
    MAb5021.250.75–1.5>100>100
Positive-control mouse IgG2a
    Anti-PorA P1.70.50.3–0.71.051.0–1.1
    Anticapsular, SEAM 120.180.15–0.21.151.0–1.2
  • 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.