Immunocompetence of inflammatory cells in rabbit testes infected with Treponema pallidum.

Systematic studies were conducted in rabbits to delineate factors favoring the predilection for multiplication of T. pallidum in testes. The results strongly suggest that, in addition to the mucoid material produced during lesion development regardless of the site of infection, a whole array of testicular substances with immunomodulatory activity may largely contribute to the propagation and delayed clearance of the pathogen from the testicular environment and most likely from the host.