[Pathogen-host relations in sexually transmitted diseases].

The host-parasite relationship between the major causative agents of sexually transmitted diseases, e.g. Neisseria gonorrhoeae, Treponema pallidum and Trichomonas vaginalis, and their target cells in the urogenital tract can generally be studied in suitable cell and organ cultures. Experience with N. gonorrhoeae predominantly gained from fallopian-tube organ cultures shows that there are several prerequisites for adherence as the first step of pathogenesis. They range from the type of bacterial pili to the type of epithelial cell. Later the function of these cells is damaged by subcellular toxins of a lipopolysaccharide nature. The cocci are phagocytosed, which eventually leads to definite (ultra-) structural alterations. These processes are not only described in detail but also compared with those found with other bacterial species and target cells. Possible predisposing factors in the host are also taken into account. Finally the need for investigating the effect of antibiotics on the host-parasite relationship is stressed.