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Synthetic DNA probes specific for either the tpf-1 gene of Treponema pallidum subsp. pallidum Nichols or the tyf-1 gene of Treponema pallidum subsp. pertenue CDC 2575 were used for hybridization with in vitro-amplified chromosomal DNAs of 10 different Treponema isolates. tpf-1 and tyf-1 differ only in one nucleotide at residue 123, and three of four syphilis strains were of the Nichols type, whereas five of six yaws strains were of the CDC 2575 type, indicating that the nucleotide at position 123 of the tpf-1 or tyf-1 gene is not a definitive trait for either T. pallidum subspecies.

A 3 1/2-year-old boy, born and living in Indonesia, experienced disseminated skin lesions and an ulcerated, crusted, papillomatous lesion on the prepuce of his penis. This location suggested venereal syphilis, but on clinical, serologic, and epidemiologic grounds a diagnosis of early yaws was made. This treponemal disease should be considered in children who have traveled to or migrated from remote tropical regions, and who have unusual skin lesions in combination with a positive treponemal serology. Although yaws is considered a rare and exotic disease in the United States and Europe, it is still widespread in some parts of the world.

By differential IgG measurements of sera of 27 patients with early infectious syphilis, it was found that infection with T. pallidium results in a preferential synthesis of IgG immunoglobulins characterized by high isoelectric points. The decrease in total IgG level observed after 6 weeks of treatment can to a large extent be accounted for by the decrease in basic IgG concentration. The relationship between the total and basic IgG levels and the number of T. pallidum present in the body during the three early stages of the disease studied is discussed.

Three fractions, containing immunoglobulin G's (IgG's) of differing relative electrophoretic mobility, were isolated from sera of 33 male patients with untreated early syphilis. Serological testing, employing four different serodiagnostic procedures for these fractions at equal amounts of IgG, revealed a very constant reaction pattern for all patients. In the earliest stages of the disease, the most basic fraction was the first to show antibody activity. In progressive stages, antibody activity subsequently was also found in the two less basic fractions. However, in all stages of disease studied, the basic part of the IgG made the largest contribution of the total antibody activity within the IgG class, indicating an uneven distribution of antitreponema antibody activity over heterogeneous IgG. Several possible explanations of the observations are discussed.

The mucopolysaccharide nature of the material deposited in rabbit testes infected with Treponema pallidum was confirmed by histochemical staining with alcian blue. Differential staining of mucopolysaccharides showed the presence of sulphated mucopolysaccharides as an almost constant feature, whereas in little more than half of the orchitic testes studied variable deposits of hyaluronic acid were seen. The treponemes were almost exclusively present in the areas rich in mucopolysaccharide. A combination staining with the Warthin-Starry method and alcian blue showed treponemes in close association with pre-existing fibrils and cells contained in these fibrils. The latter findings were confirmed by electron microscopy, and the fibroblasts to which treponemes adhered displayed the characteristics of activated cells. The close parallel between the histopathological changes observed here and their descriptions in published reports shows that our specific strain still behaves the same as the original Nichols pathogenic strain of T pallidum.

The hypothesis that experimentally determined survival times of Treponema pallidum in stored donor blood could be related to the number of treponemes initially present in the treponeme-blood mixtures was investigated by inoculating rabbits with three graded doses of treponemes suspended in donor blood and stored at 4 degrees C for various periods of time. The storage periods up to which living treponemes could be detected in the testes of the inoculated rabbits as well as those storage periods up to which seroconversion occurred are related to the number of treponemes present in the treponeme-blood mixtures. Increasing numbers of treponemes present in the donor blood resulted in longer periods up to which positive results in both parameters were found. All available evidence suggests that the upper limit of seroconversion coincides with the upper limit of treponemal survival. Inoculation with 5 X 10(4) treponemes per ml of donor blood resulted in a treponemal survival time of 48 h, inoculation with 1.25 X 10(6) treponemes per ml in a treponemal survival time of 72 h and inoculation with 2.5 X 10(7) treponemes per ml donor blood in a survival time of 120 h.

Nineteen of 23 serum samples from patients with secondary syphilis, six of 24 from patients with primary syphilis, and four of seven from patients with early latent syphilis had complement-dependent autolymphocytotoxic reactivity at 15 degrees C. After treatment, the reactivity was decreased. It was not directed only against autologous lymphocytes but also against allogeneic lymphocytes. Sephadex G-200 gel filtration showed that the lymphocytotoxins were present in the IgM-containing exclusion peak. Furthermore, serum samples that had high antibody titres in the Reiter protein complement-fixation test or Wassermann-Kolmer reaction also had a high frequency of cold-reacting autolymphocytotoxins. This indicates that the autolymphocytotoxic reactivity is related to the humoral response in syphilis.

The development of immunoglobulin G (IgG) subclass-specific anti-Treponema pallidum antibodies during the course of syphilis in humans was studied with sera from 50 untreated male patients. The patients were divided into five diagnosis groups. In the fluorescent treponemal antibody test, which delineates the presence of cross-reacting antibodies, as well as specific antitreponema antibodies, IgG1, IgG2, and IgG3 subclass antibodies were already present during the seronegative primary stage. Specific antibodies, which were detected by the fluorescent treponemal antibody absorption test, were first present during the serotype-variable primary stage. These antibodies were almost exclusively of the IgG1 and IgG3 subclasses. In later stages, antibodies of other subclasses were detectable. Titration of IgG1 antitreponema antibodies in three electrophoretically different IgG fractions revealed an asymmetric distribution in these fractions during primary syphilis. The antibodies were largely confined to the most basic fraction during primary syphilis. A sudden change in the distribution was noted between the end of the primary stage and the secondary stage; an even distribution of IgG1 antitreponema antibodies existed in the late latent stage. These findings confirm and extend previous results from our laboratory. The development of antibodies detected by both tests is discussed in terms of a sequential stimulation of the immune system due to the presence of an extracellular layer covering the treponemas or, alternatively, in terms of a suppression of the immune response during early syphilis.

It is demonstrated that IgG fractions with isoelectric points above 7.6, isolated from pooled syphilitic sera, are able to elevate the thymol turbidity. The effect increases with increasing isoelectric points of the isolated fraction. IgG from individual syphilitic patients exerts a stronger effect on the thymol turbidity than normal IgG. It is concluded that elevated amounts of these basic immunoglobulins are present in the sera of syphilitic subjects.

The influence of storage at 4 degrees C on the survival of Treponema pallidum in donor blood, artificially infected with treponemes of the virulent Nichols strain was studied. Rabbits were inoculated in each testis with 0.5 ml of the blood-treponeme mixture, containing 5 X 10(5) microorganisms/ml, which was stored for up to 336 h. Under these circumstances, the blood-treponeme mixture appeared to be infectious for up to 96 h of storage, based on the demonstration of T. pallidum and serological findings, using FTA-ABS, TPHA and VDRL tests. The two former tests were found to be equally sensitive in detecting incubating syphilis in the rabbits, the VDRL test was significantly slower in this respect. From the absence of orchitis as well as seroconversion in rabbits, inoculated with blood-treponeme mixtures stored for 120 h or longer periods of time, it is concluded that after 120 h of storage infectivity is lost. The presently found survival time of treponemes in blood between 96 and 120 h of storage is discussed in relation with survival times found by other investigators.

This article presents information on the development of IgG anti-treponema antibodies, as delineated in the FTA-ABS test in various stages during the classical course of human syphilis. It was shown that, in a FTA-ABS procedure employing treponemata spontaneously fixed to cultured cells or fibronectin layers, the treponemata failed to show fluorescence upon incubation with primary seropositive or secondary stage patient sera and conjugate. This suggests that these epitopes are covered with an extra-cellular layer, covering the treponemata.