The GPI-anchored CD52 antigen of the sperm surface interacts with semenogelin and participates in clot formation and liquefaction of human semen.

CD52 is a human glycosylphosphatidylinositol (GPI)-anchored antigen exclusively expressed in leukocytes and epididymal cells. It is also present in sperm, being inserted in their plasma membrane as they pass through the epididymis. In a previous paper we identified a new CD52 form without GPI anchor by fast performance liquid chromatography (FPLC) fractionation of semen components.

Menstrual cycle-related sialidase activity of the female cervical mucus is associated with exosome-like vesicles.

Objective: To study endogenous sialidase activity in genital tract secretions of pregnant and nonpregnant women.

Design: Laboratory study.

Setting: Department of Evolutionary Biology and Department of Obstetrics and Reproductive Medicine, University of Siena, Siena, Italy.