IMMUNITY IN EXPERIMENTAL SYPHILIS. 3. ATTENUATION OF VIRULENT TREPONEMA PALLIDIUM BY GAMMA-IRRADIATION

Miller, James N. (University of California School of Medicine, Los Angeles). Immunity in experimental syphilis. III. Attenuation of virulent Treponema pallidum by gamma-irradiation. J. Bacteriol. 90:297-301. 1965.-Virulent, freshly isolated cells of Treponema pallidum strain Nichols suspended in a 50% rabbit serum-saline solution and exposed to a gamma-irradiation dosage of 652,800 r were rendered noninfectious without apparent loss of motility or change in observable morphological and staining characteristics. Although 5 x 10(7) gamma-irradiated organisms failed to elicit an immobilizing antibody response in rabbits, the same organisms retained their capacity to react with classical T. pallidum-immobilizing antibody.

TESTS FOR SYPHILIS. THE INCREASING INCIDENCE OF BIOLOGIC FALSE POSITIVE REACTIONS AS MEASURED BY TREPONEMA PALLIDUM IMMOBILIZATION

Analysis of data obtained in 25,787 Treponema pallidum immobilization tests in a ten-year period showed an increase in the incidence of biologic false positive (BFP) reactions for syphilis, and a decrease in the incidence of reactive TPI tests. The percentage of BFP tests increased from 54.2 per cent in 1953 to 70.7 per cent in 1962. Reaction to a standard serologic test for syphilis (STS) indicates only that the patient may have syphilis. A subsequent non-reactive TPI test remains the best procedure for ruling out a diagnosis of syphilis. Thus the clinician should be made more aware of the fact that a biologic false positive reaction strongly implies the existence of another disease, the cause of which should be investigated.

SEROLOGIC DIAGNOSIS OF SYPHILIS; USE OF THE TREPONEMA PALLIDUM IMMOBILIZATION (TPI) TEST AND THE FLUORESCENT TREPONEMAL ANTIBODY (FTA) TEST

Comparative data from four different laboratories on the TPI and FTA tests on VDRL-reactive sera from patients with no symptoms of syphilis showed agreement of results of the FTA test with those obtained with the TPI test (the reference test) varying from 71 per cent to 112 per cent. The FTA test is complex and requires additional research before its use as a routine public health laboratory procedure can be recommended. The TPI test appears to be unequivocally the test of choice for the diagnosis of late and latent syphilis.

REITER PROTEIN COMPLEMENT FIXATION TEST—A Preliminary Comparison of the TPI Test with the Complement Fixation Test Employing a Soluble Protein Antigen Derived from the Reiter Strain

A comparative study of the specificity of the Reiter protein complement fixation (RPCF) test and the Treponema pallidum immobilization (TPI) test on 180 sera showed that the results in 178 instances or 98.9 per cent were in agreement. The sensitivity of the RPCF test, when compared to the TPI test, on 189 sera from patients known to have syphilis was in agreement in 182 or 96.3 per cent, assuming a correlation exists between positive TPI and both the "reactive" or "weakly reactive" RPCF test results. As to reproducibility of results, the RPCF test results agreed in 84 of the 87 sera tested (95.4 per cent). The sera were tested at least three times on different days. Anticomplementary reactions were observed in three of 91 normal sera.

Serologic diagnosis of syphilis; the use of Treponema pallidum immobilization and immune adherence tests

TPI tests were carried out on 4,060 sera. Among 3,934 patients with reactive STS and no history of syphilis, 2,148 or 54.6 per cent had negative reaction to TPI tests, 1,695 or 43.1 per cent had positive reaction and 91 or 2.3 per cent had doubtful reaction. Two hundred and ninety-two or 73.0 per cent of 400 pregnant women with reaction to STS in the absence of a history of syphilis showed negative results by TPI test, 103 or 25.8 per cent had positive results and five or 1.2 per cent had doubtful reaction.Ninety-five or 75.4 per cent of 126 patients with a history of treated syphilis had positive reaction to TPI tests, 20 or 20.2 per cent had negative reaction and nine or 9.1 per cent had doubtful reaction.TPI and TPIA tests were done on 143 sera carefully selected for the study. Among 102 sera subjected to the TPI test, 46 or 100 per cent of these positive were also positive by TPIA tests, while 52 or 94.5 per cent of 55 TPI-negative sera were also nonreactive by TPIA test. One serum gave doubtful TPI test reaction and positive TPIA test reaction.