The changes of serum
IgG antibody reactivity to
protein antigens of Treponema pallidum
after treatment of
syphilis were observed using
sodium dodecyl sulfate-
polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. Until 9 to 12 months
after treatment, it was seen that there was a loss of several
antibodies and some diminution in their reactivity in primary, secondary and early
latent syphilis, but no changes occurred in late latent and reinfected
syphilis. In
primary syphilis, there was a significant loss of two
IgG antibodies to the treponemal
antigens of molecular weights 68,500 and 47,000 at 11 months
after treatment. According to our previous study, the treponemal
antigen of molecular weight 68,500 was T. pallidum specific and appeared only in
primary syphilis, and that of molecular weight 47,000 was one of the major
antigens of T. pallidum. The reaction between serum
IgG antibodies of 14 patients who had been treated for secondary, early latent and late
latent syphilis 2 to 14 years ago and major
antigens of T. pallidum was observed and any loss or decrease in reactivity was not discovered. From the results obtained, it was concluded that the observation of serum
IgG antibody reactivity to
protein antigens of T. pallidum is not helpful in evaluating the efficacy of treatment in secondary, early latent, late latent and reinfected
syphilis. However, serum
IgG antibodies to treponemal
antigens of molecular weights 68,500 and 47,000 could possibly be useful in the assessment of the efficacy of treatment in
primary syphilis.