Recently, multiple regions in Japan have reported a sustained increase in syphilis cases, with annual confirmed infections exceeding 13,000 for four consecutive years. Epidemiological data indicate a clear shift toward younger populations, alongside a notable rise in cases among women. Once regarded as a “controllable and curable” sexually transmitted infection, syphilis is re-emerging in a more insidious and complex form, underscoring the need to move beyond textbook-level understanding of this disease.
What Is Syphilis?
Syphilis is a chronic, systemic infectious disease caused by Treponema pallidum (TP), with humans as its only known natural host. Transmission occurs primarily through sexual contact, but vertical transmission from mother to child and blood-borne transmission can also occur. Following infection, syphilis progresses through distinct clinical stages—primary, secondary, latent, and tertiary—manifesting symptoms that range from painless chancres and skin rashes to severe cardiovascular and central nervous system involvement over the course of decades.
During infection, the host immune system mounts antibody responses against multiple immunogenic proteins of T. pallidum. Among these, TmpA, TPP17, and TPP47 are consistently expressed across different stages of infection and have therefore become key molecular targets in syphilis research and serological diagnostics. Because early symptoms are often mild, atypical, or self-resolving, syphilis frequently goes unnoticed, enabling continued transmission and contributing to the resurgence observed in many countries.
Morphology and cell envelope architecture of T. pallidum（Nat Rev Microbiol. 2016 Dec;14(12):744-759.）
Structural Features of Treponema pallidum
T. pallidum is a slender, highly helical bacterium characterized by an unusually sparse outer membrane and the absence of classical lipopolysaccharide. These features confer a strong capacity for immune evasion within the host. Its periplasmic flagella enable remarkable motility, allowing the spirochete to rapidly penetrate mucosal surfaces and tissue barriers, disseminating through the bloodstream and lymphatic system.
Despite limited surface antigen exposure, several lipoproteins and periplasmic proteins are readily recognized by the host immune system. TmpA (Treponema membrane protein A) is a relatively conserved membrane-associated protein that elicits a robust humoral immune response early in infection. TPP17 (Tp17) and TPP47 (Tp47), both localized to the periplasmic space, are highly immunogenic and have demonstrated strong antigen stability and diagnostic value across multiple studies.
Mechanisms of Syphilis Infection
Syphilis infection typically begins at sites of minor skin or mucosal disruption. After local replication, T. pallidum enters the bloodstream, leading to bacteremia and systemic immune activation. The host generates antibodies against a range of treponemal antigens, with antibodies targeting TPP47 and TPP17 often detectable from early to mid stages of infection. As a result, these antigens are widely used in the development and optimization of serological assays for syphilis.
Research on TmpA suggests that this protein may play an important role in treponemal adhesion, host recognition, and immune activation, making it a valuable molecular entry point for understanding persistent infection and immune evasion in syphilis.
Serologic response to infection with Treponema pallidum, the causative agent of syphilis（MMWR Recomm Rep. 2024 Feb 8;73(1):1–32.）
At present, no vaccine is available for syphilis. Prevention therefore relies heavily on behavioral interventions and early detection. Safe sexual practices, routine sexually transmitted infection screening, and antenatal syphilis testing are critical measures for interrupting transmission and preventing severe disease outcomes.
High-Quality Antibody Tools: A Cornerstone of Research and Diagnostics
Whether in basic research aimed at elucidating treponemal antigen structure and host immune responses, or in the development and validation of clinical diagnostic assays, antibodies with high specificity and consistency are indispensable tools.
AntibodySystem offers a portfolio of high-quality antibodies targeting Treponema pallidum, designed to support immunological research, assay development, and diagnostic validation. These tools enable researchers and diagnostic developers to more precisely investigate syphilis infection mechanisms and immune responses, contributing to improved disease surveillance, prevention, and diagnostic accuracy.
Anti-Treponema pallidum tmpA Polyclonal Antibody [PXX06901]
Recombinant Protein lysates were subjected to SDS PAGE followed by western blot with tmpA antibody (PXX06901) at 1 μg/ml.
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Catalog |
Product Name |
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PXX06901 |
Anti-Treponema pallidum tmpA Polyclonal Antibody |
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PXX07001 |
Anti-Treponema pallidum TPP47 Polyclonal Antibody |
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PXX06701 |
Anti-Treponema pallidum TPP17 Polyclonal Antibody |
References
1. Talhari C, Arriel K, Serra MS, Veasey JV. Acquired syphilis: update on clinical, diagnostic and therapeutic aspects⋆. Anais Brasileiros de Dermatologia. Published online April 10, 2025.
2. Radolf JD, Deka RK, Anand A, Šmajs D, Norgard MV, Yang XF. Treponema pallidum, the syphilis spirochete: making a living as a stealth pathogen. Nature Reviews Microbiology. 2016;14(12):744-759.
3.Papp JR. CDC laboratory recommendations for syphilis testing, United States, 2024. MMWR Recommendations and Reports. 2024;73(1).
