Detection of Treponema pallidum in lesion exudate with a pathogen-specific monoclonal antibody

Abstract

The diagnosis of early syphilis currently requires dark-field microscopic or serologic demonstration of Treponema pallidum infection. Dark-field microscopy is not widely available and is complicated by the numerous saprophytic spirochetes which are present at oral and rectal mucosal surfaces. Serologic tests are positive in only 70 to 90% of patients with primary syphilis, and several days may be required for results to become available. We used a pathogen-specific, fluorescein-conjugated monoclonal antibody to examine lesion exudates from 61 patients for the presence of T. pallidum and compared the data with results of dark-field microscopy and serologic testing. The direct fluorescent-antibody technique revealed the presence of T. pallidum in 30 of 30 patients with early syphilis, and dark-field microscopy was positive for 29. Serologic tests were reactive for 27 of 30 patients with syphilis; in the 3 patients with nonreactive serologic tests, chancres had been present for 4, 6, and 21 days. Although 7 of 31 patients without syphilis had spiral organisms seen on dark-field microscopy, the direct fluorescent-antibody test was negative for all 31. The presence of nonpathogenic spirochetes was subsequently verified in 5 of 7 patients by using a second monoclonal antibody which reacts with nonpathogenic, as well as pathogenic, treponemes and related spirochetes. The demonstration of T. pallidum by using fluorescein-conjugated monoclonal antibodies is intrinsically specific and is as sensitive as dark-field microscopy for the diagnosis of early syphilis. This method provides a convenient, accurate means for the diagnosis of syphilis by health care providers, many of whom lack access to dark-field microscopy.

Use of monoclonal antibodies to enumerate spirochetes and identify Treponema denticola in dental plaque of children, adolescents and young adults

“…Sourees and expected reactivities of each mAb used in this investigation are listed in Table 1. The specificities of each mAb have been deseribed previously (5,8,13,14). Monoclonal antibody TDII, IAAll (serovar "B") will be referred to hereafter as TD-II; TDIII, IIIBB2 (serovar C) as TD-III; and BgII,VF9/ 2d as Bg.…”

Exploring the oral bacterial flora: current status and future directions

“…Detecting oral bacteria NB Parahitiyawa et al antibodies, the specificity is increased (Hook et al, 1985).…”

Comparison of molecular and microscopic techniques for detection of Treponema pallidum in genital ulcers

“…Serologic tests, however, have poor sensitivity during early disease (4,21). At initial presentation, up to 30% of patients with primary syphilis may have a negative nontreponemal serologic test (6,19,20). Although treponemal tests, such as the fluorescent treponemal antibodyabsorption test, become positive before nontreponemal tests, most laboratories perform the latter as a screening test and only confirm positive nontreponemal tests with a fluorescent treponemal antibody-absorption test.…”

“…Visualization of treponemes by dark-field microscopy is generally considered the gold standard; however, its sensitivity can vary from 79 to 97% (15,17,23). In addition, commensal spirochetes can confound the interpretation of smears of oral or anal lesions because they cannot be distinguished morphologically from T. pallidum (6,15,16,17). The application of topical agents to treat lesions can also interfere with the interpretation, leading to falsenegative results.…”

“…The application of topical agents to treat lesions can also interfere with the interpretation, leading to falsenegative results. More recently, detection of T. pallidum has been accomplished by direct fluorescent antibody (DFA) staining performed with fluorescein-conjugated polyclonal or monoclonal anti-T. pallidum antibodies (6,7,17). This test is a suitable alternative to dark-field examination and has a comparable sensitivity to it (6), and since the observation of motility is not a criterion for identification, the DFA can be performed on fixed specimens (6,7).…”