Investigations into the outer surface of pathogenic Treponema pallidum

textabstractBased on the assumption that a successful immune response to T. pallidum must, at least initially, be targetted against the outer membrane of the treponemes, the purpose of the study was to gain more insight in the accessibility of this membrane. The in vitro adherence of the treponemes to fibroblasts played a key role in the experimental studies. First, the relevance of the treponemal adherence in the in vivo infection was investigated as a part of histopathological studies. Second, since the adherence occurred at the surface of the treponemes, various factors that influenced the adherence were investigated. Third, the adherent treponemes could be used to study the accessibility of the treponemal outer membrane for anti-treponemal antibodies without the use of fixation. Sera of syphilis patients were used as the antibody source. In these patients the IgG response during the sequential stages of syphilis was characterized in order to exclude an overall immuno-suppression during this disease. Moreover, this characterization enabled the use of well-defined sera and their fractions in later studies.