FIGURE 4.

Heparin inhibits binding of HufH18–20/Fc to sialylated gonococci. Binding of HufH18–20/Fc to sialylated 252 (PorB.1A) and F62 (PorB.1B) strains was measured by flow cytometry in the presence of heparin (final concentrations of 100 or 400 units (u)/ml; denoted by the dashed line and shaded gray histograms, respectively). Binding of HufH18–20/Fc in the absence of heparin is indicated by the solid line and Control (no HufH18–20/Fc added) by the dotted line. The x axis represents fluorescence on a log₁₀ scale, and the y axis represents the number of events. One representative experiment of three independently performed experiments is shown.