Immunoperoxidase localization of treponema pallidum: its use in formaldehyde-fixed and paraffin-embedded tissue sections.

The spirochete, Treponema pallidum, the causative agent of syphilis, has been successfully localized in formaldehydefixed and paraffin-embedded tissue sections using rabbit anti-T pallidum antiserum with two immunoperoxidase techniques. These techniques, the indirect peroxidase-labeled antibody method and the peroxidase-antiperoxidase (PAP) method are compared for sensitivity and degree of nonspecific staining. Both offer substantial advantages over conventional silver-impregnation techniques, but the indirect peroxidase-labeled antibody method seems better, based on the intensity of staining and the simplicity of procedure.