Treponema pallidum was found to be not helical, but a flat wave twisted into one to five different planes per cell.

The spirochetal flora of normal female genitalia is similar to that of the male and consists of Treponema calligyrum, Treponema minutum, and Spironema refringens. The types are present in varying proportions, but the calligyrum usually predominates, and the refringens is the least frequent. The female genitalia are much richer generally in the number of spirochetes than the male.

Treponema pallidum (Nichols strain) exhibited mucopolysaccharidase activity. Acidic mucopolysaccharides were broken down more rapidly by viable treponemes than by heat-inactivated treponemes or membrane filtrates of treponemal suspensions. Ouchterlony immunodiffusion demonstrated the occurrence of antibodies to the hyaluronidase-like enzyme within syphilitic sera. After intratesticular inoculat...

Pathogen-specific membrane immunogens of Treponema pallidum subsp. pallidum (T. pallidum) have been identified previously by phase partitioning with the nonionic detergent Triton X-114. One of these antigens, a 15-kilodalton (kDa) polypeptide, is expressed in relatively small quantities in T. pallidum but is highly immunogenic in both human and experimental syphilis. The native T. pallidum anti...