Co-incubation of human spermatozoa with Chlamydia trachomatis serovar E causes premature sperm death

The aim of this work was to investigate the effect of elementary bodies (EB ) of Chlamydia trachomatis serovars E and LGV on sperm motility, viability and acrosomal status. Highly motile preparations of spermatozoa from normoz oospermic patients were co-incubated for 6 h with 0.54x10(6) EB per ml. At 1, 3 and 6 h of incubation, sperm motility was determined by computer-assis ted semen analysis (CASA) and the proportion of dead cells determined by th e hypo-osmotic swelling (HOS) test. Acrosomal status was also examined usin g a standard monoclonal antibody assay. In the absence of EB, the percentag e of motile spermatozoa remained >69% over the 6 h incubation and the propo rtion of dead spermatozoa at <12%. However, during the incubation with EB o f serovar E there was a significant decline in the percentage of motile spe rmatozoa (P < 0.05), and a corresponding increase in the proportion of dead spermatozoa (P < 0.05) at all time-points. However, following incubation w ith serovar LGV, only the percentage of dead spermatozoa after 6 h incubati on was significantly different from the control (P < 0.05). The amount of a crosome-reacted spermatozoa remained unchanged (<16%) in all incubations at all time-points. Dose-response experiments indicated that increasing the c oncentration of EB to 2.5x10(6) per ml did not significantly alter the resu lts. Furthermore, co-incubation of spermatozoa with dead EB (killed by heat treatment) abolished the chlamydia-mediated response, indicating that the effect is a result of the live organism and not soluble components or membr ane elements. These data suggest that a detrimental effect on sperm functio n by some serovars may be an as yet unrecognized component of infertility p roblems.