Scanning Electron Micrograph of the Spirochete Treponema pallidum Penetrating a Host Cell

Treponema pallidum uses adhesins found at the tip of the spirochete to adhere to receptors on the host cell. After one tip of the spirochete attaches to the host cell and some form of invasin apparently causes the host cell to release digestive enzymes that enable the spirochete with its corkscrewing motility to penetrate the host cell membrane. T. pallidum causes syphilis.

Content Provider: CDC/Dr. David Cox
Public Domain; Courtesy of the Centers for Disease Control and Prevention.