Characterization of human sperm antigens reacting with antisperm antibodies from autologous sera and seminal plasma in a fertile population

Abstract Immunoblotting techniques were used to characterize the reactivity of human sperm antigens with antisperm antibodies from a population of fertile individuals. In particular, sperm antigens of each subject were tested with the same subject's antisperm antibodies present in blood serum and seminal plasma in an attempt to construct a preliminary map of the antigen domains of the normal spermatozoon. Fifty-five fertile males, comprising 22 subjects with a pregnant partner and 33 subjects attending assisted reproductive technology sessions for proven partner's infertility and with normal semen quality entered the study. A high proportion of sera (82%) and seminal plasma (62%) showed antisperm antibodies reacting with one or more sperm antigens. Specific immunoreactivity was often demonstrated to 45-kDa, 50-kDa, 55-kDa, 69-kDa, 72-kDa and 85-kDa proteins in serum and to 59-kDa and 72-kDa proteins in seminal plasma. These proteins are the most frequently involved sperm antigens in the immune responses in fertile subjects. Further studies in an infertile population are necessary to distinguish between these antigens of minor relevance in sperm function from others significantly involved in immunological infertility.