A Fluorescent Test for Treponemal Antibodies

Deacon, Wilbur E.; Falcone, Virginia H.; Harris, Ad

doi:10.3181/00379727-96-23512

Cited by 123 publications

(41 citation statements)

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“…Outer surfaces are the first bacterial component to encounter the host and are often the targets of host adaptive immunity. Early researchers noted that antibodies in serum from infected animals did not readily bind to intact treponemes (80,202). This observation was later supported by Penn and Rhodes (231), who found that only those treponemes that had been physically disrupted reacted with anti-T. pallidum antiserum, leading them to propose that the surface of T. pallidum is nonantigenic.…”

Section: Surface Of T Pallidummentioning

confidence: 55%

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Biological Basis for Syphilis

2006

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SUMMARY Syphilis is a chronic sexually transmitted disease caused by Treponema pallidum subsp. pallidum. Clinical manifestations separate the disease into stages; late stages of disease are now uncommon compared to the preantibiotic era. T. pallidum has an unusually small genome and lacks genes that encode many metabolic functions and classical virulence factors. The organism is extremely sensitive to environmental conditions and has not been continuously cultivated in vitro. Nonetheless, T. pallidum is highly infectious and survives for decades in the untreated host. Early syphilis lesions result from the host's immune response to the treponemes. Bacterial clearance and resolution of early lesions results from a delayed hypersensitivity response, although some organisms escape to cause persistent infection. One factor contributing to T. pallidum's chronicity is the paucity of integral outer membrane proteins, rendering intact organisms virtually invisible to the immune system. Antigenic variation of TprK, a putative surface-exposed protein, is likely to contribute to immune evasion. T. pallidum remains exquisitely sensitive to penicillin, but macrolide resistance has recently been identified in a number of geographic regions. The development of a syphilis vaccine, thus far elusive, would have a significant positive impact on global health.

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Section: Surface Of T Pallidummentioning

confidence: 55%

“…Within a decade of its discovery, the TPI test was replaced by the more sensitive fluorescent treponemal antibody (FTA) test (80), later refined by an absorption step to the FTA-ABS test (149). These tests use anti-human Ig labeled with fluorescein to detect antibodies bound to T. pallidum organisms on slides.…”

Section: Antibodies In Diagnostic Testingmentioning

confidence: 99%

Biological Basis for Syphilis

2006

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“…As previously mentioned, the outer membrane of T. pallidum has an extremely low content of membrane-spanning protein (28,39), a finding which has explained the surface antigenic inertness (9,13,17,26,28) of this spirochete and its relative resistance to bactericidal antibody (2,13,23,24,30). Freeze fracture electron microscopy has demonstrated the ability of IRS antibody to aggregate TROMPs, which has been suggested to be a prerequisite for complement activation and killing of T. pallidum cells (6).…”

Section: Discussionmentioning

confidence: 87%

Sequence analysis and recombinant expression of a 28-kilodalton Treponema pallidum subsp. pallidum rare outer membrane protein (Tromp2)

et al. 1997

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In this study, we report the cloning, sequencing, and expression of the gene encoding a 28-kDa Treponema pallidum subsp. pallidum rare outer membrane protein (TROMP), designated Tromp2. The tromp2 gene encodes a precursor protein of 242 amino acids including a putative signal peptide of 24 amino acids ending in a type I signal peptidase cleavage site of Leu-Ala-Ala. The mature protein of 218 amino acids has a calculated molecular weight of 24,759 and a calculated pI of 7.3. The predicted secondary structure of Tromp2 shows nine transmembrane segments of amphipathic beta-sheets typical of outer membrane proteins. Recombinant Tromp2 (rTromp2) was expressed with its native signal peptide, using a tightly regulated T7 RNA polymerase expression vector. Under high-level expression conditions, rTromp2 fractionated exclusively with the Escherichia coli outer membrane. Antiserum raised against rTromp2 was generated and used to identify native Tromp2 in cellular fractionations. Following Triton X-114 extraction and phase separation of T. pallidum, the 28-kDa Tromp2 protein was detected prominently in the detergent phase. Alkali and high-salt treatment of purified outer membrane from T. pallidum, conditions which remove peripherally associated membrane proteins, demonstrated that Tromp2 is an integral membrane protein. Whole-mount immunoelectron microscopy of E. coli cells expressing rTromp2 showed specific surface antibody binding. These findings demonstrate that Tromp2 is a membrane-spanning outer membrane protein, the second such protein to be identified for T. pallidum.

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“…The magnitude of the concentrations of serum fractions achieved by the method employed is illustrated in Table I (Deacon, Falcone, and Harris, 1957), and the newer technique (I: 200 serum dilution) (Deacon, Freeman, and Harris, 1960 plus the mixed beta-gamma globulin fractions as measured by the VDRL slide test; reactivity was also found in the fast alpha-2 globulin. Reactivity with the Kolmer cardiolipin complement-fixation test was confined to two of the gamma globulin areas.…”

Section: Methodsmentioning

confidence: 99%