DETECTION OF COMPLEMENT CLQ RECEPTORS ON HUMAN SPERMATOZOA

C1q, the first component of the classical complement pathway, is known to play roles in promoting phagocytic events, in addition to its role in activation of complement. Although the molecular events in fertili zation leading to the entrance of the spermatozoan into the egg are no t well understood, ultrastructural observations suggest that the proce ss is quasi-phagocytic in nature. There is increasing evidence that co mplement components might play roles in fertilization. previously, we have shown that C1q promoted the agglutination of capacitated human sp erm as well as their adhesion to zona-free hamster eggs. In the presen t experiments, human spermatozoa were solubilized and, following their phase separation in Triton X-114, subject to 1-D polyacrylamide gel e lectrophoresis and immunoblotting for the presence of C1q receptors. B oth gC1q-R and cC1q-R were detected. In addition, the ability of C1q t o promote sperm agglutination was shown to be dependent upon capacitat ion, suggesting the increased expression of C1q receptors during this process. (C) 1998 Published by Elsevier Science Ireland Ltd. All right s reserved.