Characterization of lymphocyte responsiveness in early experimental syphilis. II. Nature of cellular infiltration and Treponema pallidum distribution in testicular lesions.

Abstract

The nature of the cellular infiltration and the distribution of Treponema pallidum during rabbit testicular infection were examined by immunofluorescence and light microscopy. Low numbers of treponemes are demonstrable in the perivascular regions on day 3 post-infection. On days 6, 10, and 13, large numbers of organisms are found in the interstitial spaces. The treponemes do not appear to invade the walls or lumina of the seminiferous tubules, although tubular atrophy is obvious. On days 17, 24 and 31, treponemes are no longer identifiable by immunofluorescence in infected testicles. The cellular infiltration, which is apparent on day 6, reaches its peak on day 13, corresponding to the amount of swelling observed grossly. The infiltrate is primarily lymphocytic, but macrophages are also observed during the peak cellular response. These cells are located, as are the treponemes, in the interstitial spaces. The lymphocytes are demonstrated by specific immunofluorescence to be predominantly T cells. The peak T cell infiltration in the infected testicle is followed rapidly by the disappearance of the organisms from that organ. Thus, it is postulated that infiltration by specifically sensitized T cells results in the clearance of large numbers of T. pallidum from infected tissues.

Immunization with a tri-antigen syphilis vaccine significantly attenuates chancre development, reduces bacterial load, and inhibits dissemination of Treponema pallidum

“…The attenuation of lesion progression induced by our tri-antigen vaccine is the result of careful study concerning the type of immune response that is needed to limit T. pallidum proliferation at the challenge site. Based on our earlier studies, we hypothesized that a DTH response is responsible, along with opsonic antibody, for the clearance of T. pallidum from healing primary infections, with T lymphocytes producing IFNγ to activate macrophages for phagocytosis and killing of opsonized T. pallidum [ 48 , 49 ]. In further studies, we observed that the appearance of clinical DTH at challenge sites correlated with subsequent attenuation of lesion progression [ 28 , 29 ].…”

Syphilis vaccine: challenges, controversies and opportunities

“…Mature DCs migrate to lymph nodes where they present treponemal antigens to T cells, inducing antigen-specific T cells responses. These T cells can be detected in secondary lymphoid organs of infected animals three days post-infection and progressively accumulate at the infection site (64)(65)(66), coinciding with maximal TPA burden (67,68). Rabbits infected with TPA showed a rapid hyperplasia of T cell zones in secondary lymphoid organs (lymph node and spleen) (38, 66).…”