Evaluation of an enzyme immunoassay for IgM antibodies to Treponema pallidum in syphilis in man

An enzyme immunoassay (EIA) for the detection of immunoglobulin M (IgM) antibodies to Treponema pallidum was investigated for specificity and sensitivity. Using the results in serum from 1192 patients with successfully treated syphilis, the assay was calculated to be about 97% specific. As in any other IgM enzyme linked immunosorbent assay (ELISA), rheumatoid factor played an important part in causing false positive results. Pre-absorption of serum with aggregated IgG was therefore necessary to perform the test. Evaluation of the results in serum from 385 patients with untreated primary, secondary, and latent syphilis as well as patients with untreated reinfections showed that the sensitivity of the assay depended on the stage of infection and varied between 98% and 93%. IgM antibody titres were about ten times higher in the EIA than in the indirect immunofluorescence assay using the IgM fractions of serum. From the results it may be concluded that the EIA is an appropriate technique not only for rapid and sensitive measurement of IgM antibodies in most patients with untreated syphilis but also for selecting treponemal IgM non-reactive patients.     

Evaluation of a Treponema pallidum-specific IgM enzyme immunoassay and Treponema pallidum western blot antibody detection in the diagnosis of maternal and congenital syphilis

BACKGROUND: Congenital syphilis (CS) is a result of untreated or inadequately treated maternal syphilis. CS is more likely with early stages of maternal syphilis, but most mothers lack signs or symptoms and the risk of CS is unclear. GOAL: The goal of this study was to evaluate Treponema pallidum IgM Western blot (TP IgM WB) and a T. pallidum IgM enzyme immunoassay (TP IgM ELISA) in mothers with syphilis to determine if positive tests better indicate a risk of CS than a rapid plasma reagin titer >/=1:16. STUDY DESIGN: Ninety-seven mother-baby pairs with reactive syphilis serology were evaluated. RESULTS: TP IgM WB tests were positive in 18 pregnancies (7 of 18 babies had CS) and negative in 79 pregnancies (7 of 82 babies had CS). Thirty-two mothers had titers >/=1:16 (6 babies with CS) and 65 mothers had titers /=1:16.     

Treponema pallidum specific IgM haemagglutination test for serodiagnosis of syphilis.

The Treponema pallidum specific IgM haemagglutination (TP-IgM-HA) test uses erythrocytes sensitised with antiserum to human IgM to separate IgM from IgG in serum. Specific antitreponemal IgM captured in this way is detected by adding a second reagent comprising erythrocytes sensitised with T pallidum antigen. Eighty two serum samples from 82 patients with untreated syphilis, 521 samples from 73 patients with treated syphilis, and 1872 samples from people who did not have syphilis were examined by the 19S(IgM)-TPHA (T pallidum haemagglutination), IgM-FTA-ABS (fluorescent treponemal antibody absorbed), TP-IgM-ELISA (enzyme linked immunosorbent assay), and TP-IgM-HA tests for the presence of 19S(IgM) antibodies specific to treponemes. The sensitivity of the TP-IgM-HA test was 97.6% and the specificity was 99.7%. We also traced IgM specific to treponemes in untreated patients with primary syphilis by four different tests. The TP-IgM-HA test results clearly reflected the effect of the treatment.     

Treponema pallidum specific IgM haemagglutination test for serodiagnosis of syphilis

The Treponema pallidum specific IgM haemagglutination (TP-IgM-HA) test uses erythrocytes sensitised with antiserum to human IgM to separate IgM from IgG in serum. Specific antitreponemal IgM captured in this way is detected by adding a second reagent comprising erythrocytes sensitised with T pallidum antigen. Eighty two serum samples from 82 patients with untreated syphilis, 521 samples from 73 patients with treated syphilis, and 1872 samples from people who did not have syphilis were examined by the 19S(IgM)-TPHA (T pallidum haemagglutination), IgM-FTA-ABS (fluorescent treponemal antibody absorbed), TP-IgM-ELISA (enzyme linked immunosorbent assay), and TP-IgM-HA tests for the presence of 19S(IgM) antibodies specific to treponemes. The sensitivity of the TP-IgM-HA test was 97.6% and the specificity was 99.7%. We also traced IgM specific to treponemes in untreated patients with primary syphilis by four different tests. The TP-IgM-HA test results clearly reflected the effect of the treatment.     

Quantitative microhaemagglutination assay for Treponema pallidum antibodies in experimental syphilis.

The quantitative microhaemagglutination assay for Treponema pallidum antibodies (MHA-TP) was studies in 52 untreated and treated rabbits with experimental syphilis. Rabbits with incubating experimental syphilis were cured or inadequately treated with penicillin G and some cured rabbits were later reinfected. MHA-TP conversion occurred within 45 days in untreated rabbits. Titres reached peak levels about four months after inoculation and remained relatively high for up to two years. The quantitative MHA-TP test differentiated between rabbits cured of experimental incubating syphilis and those untreated and inadequately treated. MHA-TP titres decreased after treatment given six or 12 months after inoculation but reversion did not occur. MHA-TP conversion or significant increases in titre occurred as soon as seven days after reinfection and preceded corresponding changes in a quantitative non-treponemal test. The MHA-TP is useful as a screening test for treponemal antibodies in rabbits. The quantitative MHA-TP in humans after treatment for syphilis and reinfection deserves further study.     

IgG and IgM antibody reactivity to antigens of Treponema pallidum after treatment of syphilis

The persistence or loss of IgG and IgM antibody specificities for individual polypeptides of Treponema pallidum after therapy for syphilis was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and by the Western blot technique. Both IgG and IgM antibodies to as many as 12 treponemal antigens, including a major 47-kdalton molecule, were evident in plasma from patients with untreated primary syphilis. IgM reactivity declined rapidly and uniformly after therapy, whereas IgG persisted despite some diminution in intensity of staining. Faint-to-moderate IgM and strong IgG antibody reactivities to at least 22 treponemal antigens (12-85 kdaltons) were identified in plasma from patients with untreated secondary and early latent syphilis. Again, IgG antibody declined slightly in staining intensity after treatment but continued to show reactivity against all molecules detected initially. IgM antibody reactivity declined more rapidly and was lost entirely against some determinants, including the 14- and 12-kdalton molecules. Immunofluorescence titers of IgG and IgM antibodies to T. pallidum in sera from these patients generally correlated with results of Western blot analysis. Antibody to the 12-, 14-, and 47-kdalton molecules of T. pallidum may have potential diagnostic applications.     

Microcapsule agglutination test for Treponema pallidum antibodies. A new serodiagnostic test for syphilis.

For the serodiagnosis of syphilis a quantitative passive agglutination (MCA-TP) test for antibodies to Treponema pallidum was performed with chemically stable microcapsules with no antigenic activity instead of with conventional sheep erythrocytes. The microcapsules were easily sensitised with the antigen of sonicated Treponema pallidum by treatment with glutaraldehyde. Compared with the Treponema pallidum haemagglutination test (TPHA) the MCA-TP test was superior for detecting cases of primary syphilis. Furthermore, the decrease in antibody titre during treatment was more evident in this test than in the FTA-ABS or the TPHA tests. The MCA-TP test performed on IgM and IgG gel-filtered fractions of sera from patients with syphilis proved that the sensitised microcapsule antigen reacted sharply with the IgM antibodies specific to syphilis.     

梅毒螺旋体抗体在诊断新生儿梅毒中的应用和讨论

目的:探讨梅毒螺旋体(treponema pallidum,TP)抗体在诊断新生儿梅毒中的应用。方法:分别用甲苯胺红不加热血清试验(TRUST)、TP-ELISA和密螺旋体颗粒凝集实验(TPPA)法对84例确诊新生儿梅毒患者与100例健康新生儿血清进行检测。结果:三种检测梅毒螺旋体抗体方法的灵敏度分别为51.2%、98.8%和100%,相对而言,TRUST法不适合作为诊断新生儿梅毒的初筛试验。结论:TP-ELISA法灵敏度与特异性相对较高,操作简便易行,建议作为诊断新生儿梅毒的初筛试验;TPPA法由于操作繁琐复杂,可结合临床作为新生儿梅毒的确诊试验。     

梅毒免疫和梅毒螺旋体的研究进展

梅毒螺旋体有着独特的基因和蛋白结构,对其基因分型有利于梅毒分子流行病学的研究.梅毒螺旋体缺乏脂多糖与外膜蛋白,但可表达多种脂蛋白,这些脂蛋白同梅毒螺旋体的组织黏附及播散有关,同时可诱导机体发生免疫应答.机体对于梅毒螺旋体的免疫应答过程十分复杂,固有免疫、体液免疫及细胞免疫均在梅毒螺旋体的感染过程中参与了应答过程.Th1型细胞免疫在梅毒的发生发展过程中起重要作用,梅毒患者在局部及系统免疫方面都存在细胞免疫的异常.     

An IgM capture enzyme linked immunosorbent assay to detect IgM antibodies to treponemes in patients with syphilis.

A new IgM capture enzyme linked immunosorbent assay (ELISA) was compared with the 19S(IgM) fluorescent treponemal antibody absorption (19S(IgM)FTA-ABS) test for detecting IgM antibodies to treponemes. Serum samples from 180 people, 109 with various stages of untreated syphilis, 45 with treated syphilis, and 26 non-infected, were investigated. In all diagnostic groups of syphilis the reactivity of the IgM capture ELISA was similar to that of the 19S(IgM)FTA-ABS test except in untreated neurosyphilis, for which the IgM capture ELISA was significantly less sensitive. The IgM capture ELISA was very sensitive in congenital (100%, 5/5) and primary (82%, 18/22) syphilis, but less sensitive in secondary (60%, 12/20), latent (53%, 16/30), neurosyphilis (34%, 11/32), and treated (11%, 5/45) syphilis. False positive IgM capture ELISA results were not found in five people who gave false positive Venereal Disease Research Laboratory (VDRL) reactions or in 21 neonates born to mothers adequately treated for syphilis before or during pregnancy. This indicated that the IgM capture ELISA was very specific. The course of antitreponemal IgM reactivity after treatment of early infectious syphilis was followed up in six patients. The quantity of IgM antibody declined in nearly all patients after treatment, but still remained detectable in five patients up to six months after treatment. In contrast, non-treponemal antibodies measured by the VDRL test disappeared in four out of six patients within five months from starting treatment. In conclusion, the IgM capture ELISA may be useful for easy and sensitive detection of IgM antibodies to treponemes in patients with congenital and primary syphilis. A positive test result in these cases indicates that patients should receive treatment if they have not been treated recently. The test is not, however, recommended to replace the VDRL test to monitor patients treated for syphilis.     

Production and characterization of monoclonal antibodies to Treponema pallidum.

This study was attempted to produce the monoclonal antibodies specific for Treponema pallidum and to investigate their characteristics, thereby contributing to identify the antigenic structure and to apply the diagnosis of syphilis. The seven clones (YS 3, YS 75, YS 307, YS 481, YS 343, YS 1 and YS 406) secreting monoclonal antibodies reactive with T. pallidum were produced. The isotypes of the seven monoclonal antibodies produced were defined. Optical densities of the 7 monoclonal antibodies were ranged from 0.59 to 1.48 as measured by ELISA. Monoclonal antibodies from 5 of the 7 clones which could agglutinate sheep RBC sensitized with T. pallidum, showed strong fluorescences. The monoclonal antibody from YS 343 was cross-reactive with non-pathogenic treponemes, but the other 6 monoclonal antibodies reacted with T. pallidum specifically. On immunoblotting, monoclonal antibodies from 5 of the 7 clones reacted with a polypeptide of a molecular weight of 47 kDa, and monoclonal antibodies from YS 343 reacted with a polypeptide of 64 kDa common to both T. pallidum and T. phagedenis. The above results revealed that 7 clones secreting monoclonal antibodies reactive to T. pallidum were produced successfully, and specific antibodies reacting with major antigenic polypeptides of a molecular weight of 47 kDa would be useful in the diagnosis of syphilis in the future.