FIG. 8.

Immunoblot analyses of purified recombinant PBH-512 and PBH-553 using 12 human relapsing fever sera and 3 naïve human sera (labeled A through O above immunoblots). Seven of the human relapsing fever sera (58%) reacted with recombinant PBH-512, and eight (67%) reacted with recombinant PBH-553. All human relapsing fever sera were positive, with anti-glpQ antibodies determined by enzyme-linked immunosorbent assay (ELISA) and with rGlpQ indicated at the bottom. As negative controls, experiments were also performed with three normal human sera, none of which immunoreacted significantly with recombinant GlpQ, PBH-512, or PBH-553. Bound antibodies were detected with ¹²⁵I-labeled protein A. OD, optical density.