The effect of RANTES on human sperm chemotaxis

BACKGROUND: Follicular fluid (FF) is a powerful stimulator of human sperm hyperactivation and the acrosome reaction. FF causes sperm accumulation by way of chemotaxis. The chemoattractant in FF has not yet been identified in the human. It is well known that some types of chemokine such as RANTES (Regulated on Activation Normal T Expressed and Secreted Chemokine) exist in genital tract fluids (for example, FF, seminal plasma and uterine fluid). Few reports appear to exist concerning the direct effect of chemokines on the function of human sperm. METHODS: The chemotactic effect of RANTES on human sperm were investigated by capillary and double-chamber assays, while the chemokinetic effect was investigated using computer-assisted sperm analysis. RESULTS: Both the capillary and double-chamber assays demonstrated a significant chemotactic effect of RANTES on human sperm. Anti-RANTES rabbit IgG partially neutralized the chemotactic effect of FF. In contrast, no statistically significant chemokinetic effect was observed in any motility parameter. CONCLUSIONS: Here, it was demonstrated that mRNA for the RANTES receptors CCR-1 and CCR-5 are present in human sperm. Furthermore, RANTES is involved in the chemotactic effect of FF in vitro.