Influence of testicular fluid infected with Treponema pallidum on intradermal lesions

Polyanions in syphilis: evidence that glycoproteins and macromolecules resembling glycosaminoglycans are synthesised by host tissues in response to infection with Treponema pallidum

We investigated by means of radiolabelled precursors the source and nature of the polyanionic macromolecules present in rabbit tissues during active syphilis infection. Previous studies indicated that Treponema pallidum itself does not synthesise glycosaminoglycans, at least in vitro. In replicate experiments on unilaterally infected rabbits, tissue from the orchitic testis incorporated two to three times more 35S-sulphate and 3H-glucosamine (on a wet weight basis) than tissue from the non-orchitic contralateral testis. Incorporation of 35S-sulphate was independent of the number of viable T pallidum organisms present in the infested tissue, which suggested that incorporation represented biosynthesis by the host and not the treponeme. Testes from syphilitic rabbits two days after treatment with high doses (100 mg/kg) of penicillin incorporated less 35S-sulphate than untreated infected testes, but more than normal uninfected rabbit testes. This suggests that active syphilitic infection was necessary for maximum biosynthesis of the macromolecule(s) by host tissue. Hydrodynamic profiles showed incorporation of radiolabelled precursors into two distinct fractions of different sizes, which may represent a proteoglycan and a sulphated glycoprotein. Alcian blue staining of syphilitic testes at or after peak orchitis showed focal deposition of newly synthesised polyanionic components during peak orchitis and a more generalised fibrosis in testes after peak orchitis.

Studies of rabbit testes infected with Treponema pallidum. III. Immunosuppressive activity of infiltrating mononuclear cells

When mononuclear cells infiltrating rabbit testes infected with Treponema pallidum were cocultured with autologous or homologous peripheral blood lymphocytes spontaneous stimulation and that induced by concanavalin A were suppressed. The inhibition was not due to the cytotoxic effect of the mononuclear cells or to their interference with the active site of concanavalin A (competitive inhibition). The suppressor activity was present in both T and non-T cells but was not affected by pretreatment of the mononuclear cells with indomethacin, a prostaglandin synthetase inhibitor. The suppressor activity may be intrinsic to the mononuclear cells or acquired by the cells in the testicular environment.

Mitogenic responses of hamsters infected with Treponema pertenue Lack of correlation with passive transfer of resistance

Infection of the CB/Ss Lak hamster with Treponema pertenue is characterised by chronic cutaneous lesions and lymph nodes teeming with treponemes. Throughout the course of infection lymph node and spleen cells responded poorly to the mitogens concanavalin A, phytohaemagglutinin, and lipopolysaccharide. This impairment preceded clinical signs of infection and correlated well with the chronicity of framboesial infection. High concentrations of antigen from T pertenue, but not from the non-pathogenic Treponema phagedenis, depressed the mitogenic response of normal lymphoid cells. After framboesial hamsters were treated with penicillin the mitogenic activities of their lymph node and spleen cells were similar to or slightly raised above those of controls. No significant differences were detected among recipients of framboesial immune cells with or without mitogenic activity. Recipients of immune lymph node and spleen cells from penicillin-treated or non-penicillin-treated animals had no cutaneous lesions 21 days after infection and had significantly lower lymph node weights and fewer treponemes per node than recipients of cells from normal penicillin-treated or non-penicillin-treated animals. Since lymphocyte transformation in vitro does not correlate with in-vivo treponemicidal activity, it is not a valid approach to assess the protective immune capacity of the framboesial host.

Transfer of resistance with syphilitic immune cells: lack of correlation with mitogenic activity

Hamsters infected intradermally with Treponema pallidum Bosnia A develop extensive chronic skin lesions, usually accompanied by metastatic lesions involving the paws, lips, and anal region and by lymph nodes teeming with treponemes. Throughout the course of syphilitic infection, cells from the inguinal lymph nodes responded poorly to stimulation with suboptimal, optimal, or supraoptimal concentrations of concanavalin A, phytohemagglutinin P, or lipopolysaccharide. The response of syphilitic spleen cells was variable. Depression of lymphocyte reactivity to mitogens preceded clinical signs of infection and correlated well with the chronicity of syphilitic infection. When syphilitic hamsters were treated with a curative dose of penicillin, their mitogenic responses returned to normal or were slightly elevated. No correlation existed between mitogenic activity and the ability of lymphoid cells to induce an effective immune response when transferred to normal recipients. No significant differences in protection were detected among recipients of immune cells with or without activity to mitogens. These results demonstrate that lymphocyte transformation by mitogens in vitro is not a measure of effective treponemicidal activity and so may not be a valid indicator of the protective immune status of syphilitic animals.