Isolation of a Heat-stable Antigen from Treponema Reiter, Using an Immunoadsorbent with Antibodies from Syphilitic Patients

Abstract

Antigens from T. reiteri, relevant to syphilis serology, were isolated by immunoadsorption with patients'' antibodies coupled to CNBr-Sepharose 4B. One antigen was desorbed by 2 M KSCN in 0.05 M Tris-barbital buffer, pH 8.6. The recovery was 3% and 7% in 2 experiments. A small amount of human antibodies in the isolate was removed on an immunoadsorbent column with insolubilized rabbit antibodies against normal human serum proteins. The antigen thus obtained was immunologically pure when analyzed by crossed immunoelectrophoresis. By EM of immunoprecipitates and by tandem crossed immunoelectrophoresis it was shown that the antigen differed from the flagellar antigen of T. reiteri, but was identical to antigen d previously described in T. reiteri. Antigen D was also isolated from supernatants of T. reiteri cultures. The d antigen was not denatured at pH 2.8, by 8 M urea or by 3 M KSCN; it resisted heating to 100.degree. C for 30 min. No protein could be detected in a concentrated preparation; the antigen might be a polysaccharide. Antigen d is probably present in the sorbent used in the fluorescence treponemal antibody absorption test and may constitute the active substance of this reagent.