T.pallidum p15 (Partial)

Treponema pallidum is a spirochetal bacterium responsible for syphilis, a chronic and complex sexually transmitted disease. The bacterium is known for its unique helical shape and motility, which allows it to penetrate host tissues and evade the immune system. Humans are the only known reservoir for T. pallidum .

The 15 kDa lipoprotein (p15) of Treponema pallidum is a major immunogen during natural syphilis infection in humans and experimental infection in other hosts . This protein plays a crucial role in the immune response, as it is recognized by the host’s immune system and elicits both humoral and cellular immune responses .

The recombinant p15 protein is produced using Escherichia coli (E. coli) expression systems. The E. coli-derived recombinant 6xHis-tag fusion protein is a multimer with a molecular mass of 48 kDa, containing the immunodominant regions of T. pallidum p15 and six histidines fused at the C-terminus . This recombinant protein is highly purified, with a purity greater than 90% as determined by SDS-PAGE .

The recombinant p15 protein is widely used as an antigen in various immunoassays, including ELISA and Western blots . It is an excellent antigen for the detection of T. pallidum, with minimal specificity problems . The use of recombinant proteins in immunoassays for syphilis diagnosis provides greater reliability and accuracy in the results of treponemal assays .

Several recombinant Treponema pallidum proteins, including p15, have been tested for their performance in syphilis diagnosis. These proteins are critical for achieving high accuracy in serological testing . The diagnostic potential of these proteins is validated by analysis of ROC curves, with high sensitivity and specificity scores . The use of antigenic mixtures can further improve the sensitivity of these immunoassays .