Re-investigation of the Methods for Serological Diagnosis for Syphilis

I. On the Serological Specificity of the Antigen of Treponema pallidum Reiter Strain

Abstract

Cardiolipin-CF, RPCF and TPI tests were carried out on 1, 019 serum specimens of both syphilitic and non-syphilitic persons. With non-syphilitic sera, the results by RPCF test agreed fairly well with those by TPI test; while the former test overlooked some of the weakly positive cases (17 among 1, 019). The antigenic specificity of Reiter strain of Treponema pallidum was analyzed by complement fixation and gel diffusion precipitation tests. The following results were obtained: 1) The main component of the antigen for the RPCF test was precipitated with ammonium sulfate at 75 percent saturation from the sonicate of the organisms. The antigen was immunologically distinct from cardiolipin. 2) Reiter strain shared an antigen with a virulent treponemal strain (Nichols). This antigen constituted a partial antigen of the virulent strain as the results of the gel diffusion precipitation test indicated. 3) Syphilitic human sera contained an antibody which reacted with another antigen present only in the virulent strain.
These observations may partly explain the inconsistent results in serological tests with Reiter strain and those with the virulent strain.