Development of a technique for monitoring the contamination of human semen samples with leukocytes

Objective: To determine whether receptors for the N-formyl chemotactic peptide, FMLP, exist on the surface of human spermatozoa and regulate reactive oxygen species generation by these cells. Design: Chemiluminescent analysis of reactive oxygen species generation by suspensions of human spermatozoa before and after removal of leukocytes using a magnetic cell separation technique. Setting: Academic Research Institute. Patients: Unselected male volunteers. Results: Human sperm suspensions responded to FMLP and phorbol ester (PMA) with a burst of reactive oxygen species production. Autoradiographic analyses employing H-3 FMLP and chemiluminescence studies involving the selective removal of leucocytes with anti-CD 45-coated magnetic beads demonstrated that the FMLP responses were because of leukocyte contamination. In contrast, reactive oxygen species production in response to PMA appeared to reflect the oxidant-generating capacity of both leukocytes and spermatozoa. Conclusion: The only cells present in the human ejaculate possessing detectable receptors for FMLP and capable of generating reactive oxygen species in response to this reagent come from the leukocyte population. Luminol-dependent, FMLP-induced, chemiluminescence provides a rational basis for monitoring the presence of leukocytes in suspensions of human spermatozoa.