Western blot of total bacterial extracts showing electrophoretic migration of clone12 (1), clone12pilT− (2), and clone12pilT+ (3). Total bacterial extracts were run in SDS/PAGE, 12% acrylamide, and 3 M urea and transferred to nitrocellulose. The 13C5 mAb (generous gift of L. Brossay), which is directed against the PilT protein of N. gonorrhoeae, was used for PilT detection.