FIG. 10.

Synergistic effect of anti-native Fi and Pb antibodies on neutralizing activity. The anti-native Fi and anti-Pb antibodies were purified after incubation of serum from Pt-1 (diluted 1/100) on immunoblots containing trimeric native Fi proteins or Pb proteins. The purified antibodies were used to determine the neutralizing activity. Human anti-native Fi antibodies (anti-Fi), anti-Pb antibodies (anti-Pb), and the mixture of the two antibodies (anti-Fi + anti-Pb) were used in the neutralization experiments. A negative control experiment was performed with mock proteins. The same serum was incubated on immunoblots containing mock proteins. After being washed, the membrane was incubated with an elution solution. The solution (mock) was tested for neutralizing activity. The neutralizing activities are given as percentages and are the means and standard deviations of two individual triplicate experiments.