Identity of Treponema pallidum subsp. pallidum polypeptides: Correlation of sodium dodecyl sulfate‐polyacrylamide gel electrophoresis results from different laboratories

As the first step in a cooperative effort to standardize the identification of the polypeptides of Treponema pallidum subsp. pallidum, the sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) results obtained in 16 laboratories were compared. Although it was possible to correlate the positions of 16 of the major polypeptide bands, the cross‐identification of many of the polypeptides was ambiguous, particularly in the low molecular weight range. Two‐dimensional electrophoresis provided an improved means of separating and characterizing T. pallidum polypeptides as isolated molecular species. An approach to the unambiguous identification of treponemal polypeptides was outlined which will utilize two‐dimensional electrophoresis in combination with specific properties attributable to individual proteins, including reactivity with monoclonal antibodies or monospecific antisera, biochemical and structural properties, and sequence information. To demonstrate the feasibility of this approach, two‐dimensional electrophoresis in conjunction with immunoperoxidase staining was used to specifically identify three cloned T. pallidum proteins.