In vitro tests of the adherence of Chlamydia trachomatis to human spermatozoa.

Chlamydia trachomatis is one of the most common causative agents of ascending genital infection. The mechanisms by which microorganisms spread to the upper genital tract are, however, by and large still unknown. Attachment of serovars D, H, and I of C. trachomatis to human spermatozoa was observed in in vitro experiments. The specimens were studied by immunofluorescence tests using monoclonal antibodies to C. trachomatis and transmission electron microscopy. The adherence of chlamydiae to spermatozoa was enhanced by increasing the acidity of the test environment, that is, from pH 8.0 to 4.0, by increasing the concentration of chlamydial cells in relation to spermatozoa, and by increasing the incubation time (up to 1 hour). Sperm penetration tests, using capillary tubes filled with albumen from hen's eggs, revealed that spermatozoa, when progressing forward, can carry chlamydiae attached to them.