Sequence conservation of glycerophosphodiester phosphodiesterase among Treponema pallidum strains

Previous investigations have demonstrated that immunization with Treponema pallidum subsp. pallidum glycerophosphodiester phosphodiesterase significan tly protects rabbits from subsequent treponeme challenge. In this report, w e show that the glycerophosphodiester phosphodiesterase amino acid sequence is conserved among 12 strains from a total of five pathogenic treponemes. The invariant nature of this immunoprotective antigen makes it an attractiv e candidate for inclusion in a universal subunit vaccine against T. pallidu m infection. In addition, these studies show a silent nucleotide substituti on at position 579 of the gpd open reading frame which is consistently obse rved in the non-T. pallidum subsp. pallidum strains. This sequence alterati on introduces a PleI restriction site in the nonsyphilis strains and thus a llows genetic differentiation from T. pallidum subsp. pallidum strains.