Human sperm membrane antigens extracted by deoxycholate （DOC） were used to immunize BALB/c mice.Hybrid cell lines secreting sperm-specific monoclonal antibodies were generated by cell fusion in a semi-solid medium and screened by indirect immunofluorescent assay using live and methanol-fixed sperm.Out of 850 hybrid clones from cell fusion

28 were shown to secrete sperm-specific antibodies which reacted with the acrosome

equatorial segment

whole surface plasma membrane or tail of spermatozoa.Finally

seven hybrid cell lines were established and shown to secrete monoclonal antibodies which had no cross-reactivity with arty human tissues other than testis and sperm.The majority were also shown to inhibit fertilization of mouse oocytes in vitro and human sperm penetration of zona-free hamster ova.Western blot analysis revealed that some of these antibodies reacted with sperm membrane antigens of distinct molecular size.