Resistance of Specifically-Sensitized Treponema pallidum to Methylene Blue Stain.

Abstract

Virulent T. pallida, which are normally stained by methylene blue, become resistant to the dye following incubation with syphilitic serum and complement. The responsible factor in syphilitic serum is associated if not identical with treponemal immobilizing antibody, and distinct from the antibody concerned in reactions with cardiolipin antigens. The reaction provides the basis for a specific diagnostic test for syphilis.