FIG. 9.

Competitive binding ELISA analyses of fH and Ab binding to BBL39. All methods were as described in the text. In brief, BBL39 was immobilized in the wells of a 96-well microtiter plate in triplicate. Normal human serum (open bar) or purified hfH (shaded bar) was added, wells were washed, and infection sera (mouse) were added. Binding of mouse IgG to BBL39 was assessed by using rabbit anti-mouse IgG antisera. As a control for fH binding to immobilized BBL39, one set of wells was incubated with fH (solid bar) and washed, goat anti-fH antisera were added, wells were washed, and a rabbit anti-goat secondary Ab was added. To verify that anti-OspE IgG was able to bind to the immobilized BBL39, infection sera were added to one set of wells (crosshatched bar), wells were washed, and IgG binding was detected by using rabbit anti-mouse IgG. Detection methods were as described in the text. Data are average readings from three wells. Error bars, standard deviations.