Molecular analysis of immunoglobulins M and G immune response to protein antigens of Treponema pallidum in human syphilis

Abstract

Protein antigens of T. pallidum precipitated by IgM and IgG antibodies of sera from patients with untreated primary and secondary syphilis and treated secondary syphilis were characterized on a molecular basis. T. pallidum was labeled internally with [35S]methionine and solubilized in 0.1% sodium dodecyl sulfate[SDS]-1% Triton X-100. SDS-polyacrylamine gel electrophoresis on 12.5% gels followed by autoradiography revealed 32 distinct proteins with MW of 13,500-200,000. Proteins (23) of T. pallidum with MW of 15,500-115,000 were identified as antigens by double antibody radioimmunoprecipitation with IgM and IgG antibodies of sera from syphilitic patients. The molecular analysis of the IgM and IgG immune response to T. pallidum in human syphilis is in accord with earlier immunological observations. Utilizing syphilitic human sera, 15 protein antigens of T. pallidum that are common to T. phagedenis were characterized by partial absorption of IgM and IgG antibodies with an ultrasonicate of T. phagedenis.