CHANGES IN IMMUNOCHEMICAL LOCALIZATION OF ACROSOMAL AND SPERM PROTEINS IN BOAR SPERMATOZOA DURING CAPACITATION AND INDUCED ACROSOME REACTION

Three monoclonal antibodies that stained acrosin of 55, 53, 45 and 38 kDa (ACR.2), acrosomal protein of 28 kDa (ACR.4) and sperm protein of 17 kDa (ACR.3) were used for immunostaining and immunoblotting analysi s of boar spermatozoa before and during capacitation and ionophore-ind uced acrosome reaction. Two proteins (acrosin and the 28 kDa protein) showed similar changes in the acrosome during capacitation and induced acrosome reaction. For detection of these proteins, immunoelectron mi croscopy was also used. The immunofluorescence test revealed that most spermatozoa lost acrosin and the 28 kDa protein after incubation with ionophore A 23187. The lost proteins were detected in the culture med ium by immunoblotting. During capacitation and induced acrosome reacti on, sperm protein of 17 kDa (ACR.3) showed a different pattern of labe lling. The changes in relocation of specific proteins during capacitat ion and acrosome reaction support a concept of physiological preparati on of spermatozoa for sperm-egg interaction.