THE DEVELOPMENT OF AN ENZYME-LINKED IMMUNOSORBENT ASSAY(ELISA) FOR THE DETECTION OF ANTIBODIES TO TREPONEMA PALLIDUM SUBSPECIES PALLIDUM

Abstract

An enzyme linked immunosorbent assay (ELISA) was developed for the detection of specific antibodies to Treponema pallidum subspecies pallidum, the causative agent of syphilis. When compared to a commercial (DCL) Syphilis G ELISA, the newly developed Syphilis ELISA was found to have a relative sensitivity of 98.7%, a relative specificity of 99.5%, and overall agreement of 99.3%. The assay was also shown to have a relative sensitivity of 92.7%, a relative specificity of 99.5%, and 97.5% agreement when compared to the FTA-ABS Assay, the current assay of choice for the confirmation of treponemal antibodies produced in response to syphilis infection. The Syphilis ELISA showed excellent intra-assay and inter-assay reproducibility. There was < 10% intra-assay coefficient of variation when a set of six serum samples with different antibody levels were run on the Syphilis ELISA, and replicated at least eight times within each assay. There was < 20% inter-assay coefficient of variation when the same six samples were run on the Syphilis ELISA on three separate days. Accelerated stability testing was initiated on the solid phase antigen coated plates used in the Syphilis ELISA. The data accumulated showed that the antigen coated plates were stable at least eight weeks when stored at 2-8°C. Accelerated stability testing was also completed for eight weeks with plates stored at 22-25°C, 37°C, and 45°C. The data generated showed that there was acceptable stability at both 37°C, and 45°C for at least eight weeks. Overall, it was shown that a sensitive, specific ELISA was developed for the detection of antitreponemal antibodies. The Syphilis ELISA demonstrated sensitivity and specificity comparable to that of the DCL Syphilis G Assay and the FTA-ABS test. The Syphilis ELISA will be a rapid, objective alternative for the confirmation of a syphilis infection.