T.pallidum p15
Description
Introduction
Treponema pallidum p15 is a recombinant antigen derived from the pathogenic subspecies Treponema pallidum subsp. pallidum, the causative agent of syphilis. This 15 kDa protein is a critical component of the bacterium’s inner membrane lipoproteins and serves as a major immunodominant epitope during infection. It is widely used in diagnostic assays and vaccine research due to its high reactivity with human sera and association with immune evasion mechanisms .
Protein Localization
p15 is localized to the inner membrane of T. pallidum, where it interacts with peptidoglycan and periplasmic components. Its lipidation and membrane anchoring enable immune recognition and evasion .
Biological Role in Pathogenesis
p15 is part of the bacterium’s lipoprotein network, which facilitates immune evasion and host attachment. Key functions include:
-
Immune Modulation: p15 is recognized by CD4+ T cells, contributing to immune memory and persistence of infection .
-
Structural Integrity: Interacts with peptidoglycan and periplasmic flagella, aiding motility in viscous environments (e.g., mucosal barriers) .
-
Subspecies-Specific Antigenicity: While serologically indistinguishable between T. pallidum subspecies, p15 reacts strongly with sera from infected humans .
Diagnostic Use
p15 is a core component of syphilis diagnostic kits due to its high sensitivity and specificity.
Research Insights
-
Post-Treatment Monitoring: Reactivity to p15 decreases post-antibiotic therapy, correlating with RPR titer reduction .
-
Immune Memory: p15-specific CD4+ T cells persist in blood and skin for >10 years post-treatment, indicating long-term immune recall .
-
Vaccine Development: p15 is a candidate for subunit vaccines due to its conserved epitopes and immune-activating properties .
Key Studies
-
Immune Response Dynamics
-
Genetic and Epitope Mapping
Product Specs
Product Science Overview
Treponema pallidum is the bacterium responsible for syphilis, a chronic and complex sexually transmitted disease. The bacterium is a spirochete, characterized by its spiral shape, and humans are the only known reservoir for this pathogen . One of the major immunogens of Treponema pallidum is the 15 kDa lipoprotein, commonly referred to as p15 .
The p15 protein is a significant immunodominant antigen during syphilis infection. It plays a crucial role in the immune response, with both humoral and cellular responses targeting this protein as the infection progresses . The immune response to p15 typically appears late in the infection, coinciding with the development of resistance to reinfection .
Recombinant p15 is produced using E. coli as a host. The recombinant protein is often tagged with a 6xHis-tag at the C-terminus, which facilitates its purification and detection . The resulting protein is a multimer with a molecular mass of approximately 48 kDa . This recombinant form retains the immunodominant regions of the native p15 protein, making it an excellent antigen for use in diagnostic assays such as ELISA and Western blots .
Recombinant p15 is primarily used as an antigen in various diagnostic tests to detect syphilis. Its high specificity and immunoreactivity with sera from infected individuals make it a valuable tool in serological testing . Additionally, research into the p15 protein and its immune response can contribute to the development of vaccines and improved diagnostic methods for syphilis .
Studies have shown that the p15 protein is conserved among different subspecies and strains of Treponema pallidum, as well as other pathogenic treponemes . This conservation suggests that p15 could be a target for broad-spectrum diagnostic tests and potential vaccines . Ongoing research aims to further understand the immunological properties of p15 and its role in the pathogenesis of syphilis .
