RESUMO
PROBLEM: Biological significance of increased number of leukocytes in ejaculate remains a subject of controversy. The aim of this research was to describe the morphological characteristics of the sperm elimination by leukocytes in in vivo and in vitro conditions using natural stimulator of the immune system--uropathogenic Escherichia coli, O75:HNT, isolated from semen. METHOD OF STUDY: The study was performed on ejaculated spermatozoa from normozoospermic men with leukocytospermia (n=10, in vivo experiment) or without leukocytospermia (n=15, in vitro experiment). Morphological observations were performed using light and scanning electron microscopy. RESULTS: Sperm removal by active leukocytes mediated by traditional phagocytosis and generation of extracellular traps were observed in in vivo and in vitro experiments. CONCLUSION: Our morphological data suggest that human germ cells activate leukocytes triggering both traditional phagocytosis and a novel trapping mechanism, followed by extensive sperm elimination.
