Antiserum to the 33,000-dalton periplasmic-flagellum protein of "Treponema phagedenis" reacts with other treponemes and Spirochaeta aurantia.

"Treponema phagedenis" periplasmic flagella (PF) have two major protein bands at molecular weights of 33,000 and 39,800 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (R. J. Limberger and N. W. Charon, J. Bacteriol. 166:105-112, 1986). By use of Western blotting and a polyclonal antiserum directed toward the 33,000-molecular-weight PF protein, cell lysates of 12 species of spirochetes were surveyed for reactivity. Eight species of Treponema as well as Spirochaeta aurantia were positive. The results suggest that epitopes residing on the 33,000-molecular-weight PF protein of "T. phagedenis" are evolutionarily well conserved among the spirochetes.